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SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

COMMISSION FILE NUMBER: 0-24484

MPS GROUP, INC.

(Exact name of registrant as specified in its charter)

(Registrant’s telephone number including area code): (904) 360-2000

Securities registered pursuant to Section 12(b) of the Act:

Indicate by a check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

Yes  x    No  ¨

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  x

Indicate by a check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act.):Yes    ¨    No  x

The aggregate market value of the voting stock held by non-affiliates of the Registrant, based upon the closing sale price of common stock on, June 30, 2005, the last business day of the registrant’s most recently completed second fiscal quarter, as reported by the New York Stock Exchange, was approximately $950,063,171.

As of March 1, 2006 the number of shares outstanding of the Registrant’s common stock was 104,814,551.

DOCUMENTS INCORPORATED BY REFERENCE.

Portions of the Registrant’s Proxy Statement for its 2005 Annual Meeting of shareholders are incorporated by reference in Part III.

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This Annual Report on Form 10-K contains forward-looking statements that are subject to certain risks, uncertainties or assumptions and may be affected by certain factors, including but not limited to the specific factors discussed in Part I, Item 1A under ‘Risk Factors,’ in Part II, Item 5 under ‘Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities’, and Part II, Item 7 under ‘Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources.’ In some cases, you can identify forward-looking statements by terminology such as ‘may,’ ‘should,’ ‘could,’ ‘expects,’ ‘plans,’ ‘indicates,’ ‘projects,’ ‘anticipates,’ ‘believes,’ ‘estimates,’ ‘appears,’ ‘predicts,’ ‘potential,’ ‘continues,’ ‘can,’ ‘hopes,’ ‘perhaps,’ ‘would,’ or ‘become,’ or the negative of these terms or other comparable terminology. In addition, except for historical facts, all information provided in Part II, Item 7A, under ‘Quantitative and Qualitative Disclosures About Market Risk’ should be considered forward-looking statements. Should one or more of these risks, uncertainties or other factors materialize, or should underlying assumptions prove incorrect, actual results, performance or achievements of the Company may vary materially from any future results, performance or achievements expressed or implied by such forward-looking statements.

Forward-looking statements are based on beliefs and assumptions of the Company’s management and on information currently available to such management. Forward looking statements speak only as of the date they are made, and the Company undertakes no obligation to publicly update any of them in light of new information or future events. Undue reliance should not be placed on such forward-looking statements, which are based on current expectations. Forward-looking statements are not guarantees of performance.

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PART I

References to “we”, “our”, “us”, “MPS” or the “Company” in this Annual Report on Form 10-K refer to MPS Group, Inc. and its consolidated subsidiaries, unless the context requires otherwise.

Overall

MPS Group, Inc. is a leading provider of business services with over 190 offices throughout the United States, Canada, the United Kingdom, and continental Europe. We deliver specialty staffing, consulting and business solutions to virtually all industries in the following disciplines, through the following primary brands:

Our strategy is to focus on increasing revenue and profits, through a combination of internal growth and acquisitions, primarily within our core disciplines and, to a lesser extent, expansion into new specialties. Specifically, we aim to maintain a leadership position in our IT-related disciplines, while growing our professional-related disciplines both organically and through acquisitions, which should result in the Professional Services Division providing a larger overall percentage contribution to our total revenues. The key elements to our internal growth strategy include:

While we look to strengthen relationships with our clients, we are not dependent upon a single customer or a limited number of customers.

Pursuant to our acquisition strategy, we acquired eleven businesses from 2003 to 2005: four legal staffing businesses acquired in February of 2003, August of 2003, August of 2004, and October of 2004; three health care staffing businesses acquired in February of 2004, March of 2004, and September of 2005; four accounting and finance staffing businesses acquired in February of 2004, July of 2004, October of 2004, and September of 2005; and two IT Solutions businesses, acquired in July of 2005 and September of 2005. The accounting and financing business and IT solutions business acquired in September of 2005 were part of the same acquisition. The businesses acquired in 2005, 2004, and 2003, had a combined annualized revenue of $25 million, $95 million, and $22 million at acquisition date, respectively.

In addition, we look to focus our efforts intensely on our core businesses. Toward this end, we have divested certain businesses we deemed not central to our strategy, including the 2003 sale of our outplacement unit, and the 2004 sale of our retained executive search unit. We feel we are able to execute and profit from our internal growth and acquisition strategies due to our strong management team, our integrated and scalable back office support services, and to the continued development of our strategic management information systems.

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In all of our markets and disciplines, we encounter aggressive and capable competition, with a number of firms offering services similar to ours on a national, regional or local basis. Our ability to compete successfully depends on our reputation, pricing and quality of service provided, our understanding of clients’ specific job requirements, and our ability to provide qualified personnel in a timely manner.

The Company was incorporated under the laws of the State of Florida in 1992 under the name Accustaff Incorporated, and changed its name to MPS Group, Inc. in 2002. Our principal executive offices are located in Jacksonville, Florida. Strategically, our operations are coordinated primarily from facilities in Jacksonville, Florida, and London, England, and to a lesser extent, Burlington, Massachusetts. Both of our Jacksonville and London facilities provide support and centralized services to our offices in the administrative, marketing, public relations, accounting, training and legal areas. Regional and local office managers are responsible for most activities of their offices, including sales, local and regional marketing and recruitment.

Segments

We present the financial results of our operations under our four reporting segments: North American Professional services, European Professional services, North American IT services and European IT services. In addition, we have both a Professional services and an IT services division. The Professional services division is comprised of both the North American Professional services segment and the European Professional services segment. The IT services division is comprised of both the North American IT services segment and the European IT services segment. The table below highlights the percentage contribution of revenue and gross profit from our four segments for 2005 and 2004:

Additional financial information relating to our segments can be found in Footnote 15 to the Consolidated Financial Statements.

Professional Services division

Our Professional services division provides specialized staffing and recruiting in the disciplines of accounting, finance staffing, law, engineering and healthcare for varying periods of time to companies or other organizations (including government agencies) that have a need for such personnel, but are unable to, or choose not to, engage certain personnel as their own employees. Businesses increasingly view the use of temporary employees as a means of controlling personnel costs and converting the nature of such costs from fixed to variable. Examples of client needs for staffing solutions include the need for specialized or highly-skilled personnel for the completion of a specific project or subproject, substitution for regular employees during vacation or sick leave, and staffing of high turnover positions or during seasonal peaks.

We operate this division under a variable cost business model whereby revenue and cost of revenue are primarily recognized and incurred on a time-and-materials basis. The vast majority of the billable consultants are compensated on an hourly basis only for the hours which are billed to our clients.

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Clients also hire our skilled consultants on a permanent basis, whether it is from a conversion of a temporary assignment to, or a direct placement of, a full-time position. We earn a one-time fee for these services. These fees represent approximately 6% of this division’s revenue.

The principal national and international competitors of our Professional services division include Robert Half International Inc., Resources Connection, Inc., Spherion Corporation, Kelly Law Registry, Ajilon Consulting (a wholly owned subsidiary of Adecco SA), Michael Page International, Robert Walters PLC, Hays PLC, Cross Country Healthcare, Inc., and CDI Corporation.

North American Professional Services segment

Our North American Professional services segment goes to market under the primary brands and operating units Entegee, Special Counsel, Accounting Principals, and Soliant Health. The demands of our clients (the need for confidentiality, accuracy and reliability, cost-effectiveness, and frequent peak workload periods) are similar among the businesses within this segment.

Entegee

Entegee provides technical and engineering strategic workforce solutions. From on-site management consulting and in-house project services to temporary and direct placement, Entegee combines industry knowledge and experience to fill highly skilled technical and engineering positions. These positions include, but are not limited to, engineers, designers, drafters, inspectors and assemblers. Entegee operates through a domestic network of national practice branches with offices in 10 markets, and employs approximately 2,700 billable consultants. Entegee also provides engineering and drafting design services through two company-owned centers that utilize state-of-the-art computer technology. Its primary clients include government and defense contractors, manufacturing and engineering companies.

Special Counsel

Special Counsel staffs temporary and full-time employees in attorney, paralegal, legal administrative and legal secretarial positions for workload management, litigation support, business transaction support, pre-litigation and document management support, as well as medical document review, deposition digesting, court reporting and other trial-related services. Special Counsel has a network of 37 offices across the United States, and employs approximately 1,700 billable consultants. Its primary clients are Fortune 1000 companies and law firms.

Accounting Principals

Accounting Principals specializes in placing temporary and full-time employees in accounting and finance positions. Accounting Principals has a network of 40 offices across the United States, and employs approximately 1,400 billable consultants.

In 2005, we expanded Accounting Principals’ geographic footprint with the acquisition of Pacioli Companies in September. Pacioli Companies provides high-end accounting candidates to clients primarily located in the Minneapolis, St. Paul, Minnesota area.

Soliant Health

Soliant Health specializes primarily in placing traveling healthcare professionals, in the areas of nursing, physical and occupational therapy, along with imaging technicians. Soliant Health employs approximately 700 consultants, and its clients include hospitals and healthcare providers across the United States.

In 2005, we expanded Soliant Health’s service line with the acquisition of Bilingual Therapies in September. Bilingual Therapies provides bilingual and monolingual Speech Language Pathologists (SLPs) to

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school systems throughout the country. Bilingual Therapies is the national market leader in the placement of bilingual SLPs.

Dispositions

In 2003, we sold certain operating assets and transferred certain operating liabilities of our outplacement unit. The decision to sell our outplacement unit was in keeping with our long-term strategy of focusing on our core businesses. As a result of the sale of our outplacement unit and in accordance with Generally Accepted Accounting Principles (GAAP), our Consolidated Financial Statements and Management’s Discussion and Analysis of Financial Condition and Results of Operations report the results of operations of this unit as Discontinued Operations for all periods presented. In 2004, we sold certain assets and transferred certain liabilities of our retained executive search brand.

European Professional Services segment

Since 1980, our European professional services business, Badenoch & Clark, has specialized in placing temporary, full-time, contract and interim recruitment employees in accounting and finance, financial services, legal, human resources, and marketing positions. Badenoch & Clark has 19 offices across the United Kingdom and an office in Luxembourg. Badenoch & Clark employs approximately 4,200 billable consultants.

IT Services division

Our IT services division provides specialty staffing, consulting and business solutions under the brands/operating units Modis, Modis International, Idea Integration and Beeline. We utilize the brand Modis in both our North American and European segments; however, the overall business culture distinguishes the operation of these two segments.

We operate this division primarily under a variable cost business model whereby revenue and cost of revenue are primarily recognized and incurred on a time-and-materials basis. The vast majority of the billable consultants are compensated on an hourly basis only for the hours which are billed to our clients. Approximately 1% of this division’s revenue is generated from fees for clients directly hiring our consultants.

The principal national and international competitors of our IT services division include Keane, Inc., Computer Horizons Corp., Comsys IT Partners, Inc., CIBER, Inc., Computer People (a division of Ajilon Group), Hays PLC, Elan, Lorien PLC, and Sapient Corporation. In addition, we may compete against the internal management information services and IT departments of our clients and potential clients.

North American IT Services segment

Modis

Modis specializes in the placement of IT contract consultants for IT project support and staffing, recruitment of full-time positions, project-based solutions, supplier management solutions, and on-site recruiting support for application development, systems integration, and enterprise application integration. Modis has a network of 44 offices across the United States, and employs approximately 3,700 billable consultants. Its primary clients are Fortune 1000 companies.

Idea Integration

Idea Integration specializes in Web design and development, information management solutions, wireless workflow applications, portal solutions, and enterprise resource management. Idea utilizes both salaried and

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hourly consultants to deliver solutions primarily under time-and-materials contracts and to a lesser extent under fixed-fee contracts. It operates in certain markets across the United States and its clients include Fortune 1000 companies, government and middle-market companies.

In 2005, we expanded Idea Integration’s geographic footprint with the acquisitions of two IT solutions businesses: Encore Development in July and Pacioli Companies in September. Encore Development is a Florida-based IT solutions company specializing in Microsoft development capabilities with clients primarily located in northeast Florida. Pacioli Companies provides IT programmers, statistical analysts, modelers, architects, and implementers to clients using SAS Software.

Beeline

Beeline is our software-based human capital management services solution that automates the acquisition and management of both full-time and contingent workers. Beeline operates primarily in the United States and its’ clients are principally Fortune 1000 companies.

Beeline maintains a full-time staff to support its operations and seeks to collect a service charge based upon the usage of this service. Subsequent to the initial start up costs and time, minimal cost and resources are required for the usage of Beeline’s services.

European IT Services segment

Our European IT services segment is comprised of Modis International. Modis International, headquartered in the United Kingdom, specializes in providing IT contract consultants throughout the United Kingdom and certain continental European markets. Modis International has been in operation for over 30 years. It has 11 offices across the United Kingdom, and an office each in Belgium, Germany, and the Netherlands. It employs approximately 2,100 billable consultants.

Employees

MPS employs approximately 16,800 consultants and approximately 2,600 full-time staff employees. Approximately 250 of the employees work at corporate headquarters.

As described below, in most jurisdictions, we, as the employer of the consultants or as otherwise required by applicable law, are responsible for employment administration. This administration includes collection of withholding taxes, employer contributions for social security or its equivalent outside the United States, unemployment tax, maintaining workers’ compensation and fidelity and liability insurance, and other governmental requirements imposed on employers. Full-time employees are covered by life and disability insurance and receive health insurance and other benefits.

Government Regulations

Outside of the United States and Canada, the staffing services industry is closely regulated. These regulations differ among countries but generally may regulate: (i) the relationship between us and our temporary employees; (ii) registration, licensing, record keeping, and reporting requirements; and (iii) types of operations permitted. Regulation within the United States and Canada has not materially impacted our operations.

In many countries, including the United States and the United Kingdom, staffing services firms are considered the legal employers of the temporary consultants while the consultant is on assignment with a

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company client. Therefore, laws regulating the employer/employee relationship, such as tax withholding or reporting, social security or retirement, anti-discrimination, and workers’ compensation, govern us. In other countries, staffing services firms, while not the direct legal employer of the consultant, are still responsible for collecting taxes and social security deductions and transmitting such amounts to the taxing authorities.

Intellectual Property

We seek to protect our intellectual property through copyright, trade secret and trademark law and through contractual non-disclosure restrictions. Our services often involve the development of work and materials for specific client engagements, the ownership of which is frequently assigned to the client. We do at times, and when appropriate, negotiate to retain the ownership or continued use of development tools or know how created or generated by us for a client in the delivery of our services, which we may then license or use in the delivery of our services to other clients.

Seasonality

Our quarterly operating results are affected by the number of billing days in the quarter and the seasonality of our customers’ businesses. Demand for our services has historically been lower during the calendar year-end, as a result of holidays, through February of the following year. Extreme weather conditions may also affect demand in the early part of the year as certain of our clients’ facilities are located in geographic areas subject to closure or reduced hours due to inclement weather. In addition, we experience an increase in our cost of sales and a corresponding decrease in gross profit and gross margin in the first fiscal quarter of each year, as a result of certain U.S. state and federal employment tax resets.

Access to Company Information

Our common stock is listed on the New York Stock Exchange (‘NYSE’) under the ticker symbol ‘MPS’. Our Internet address is www.mpsgroup.com. We make available through our Internet website our annual reports on Form 10-K, quarterly reports on Form 10-Q, and current reports on Form 8-K, as soon as reasonably practicable after filing such material with, or furnishing it to, the Securities and Exchange Commission. The information contained on our website, or on other websites linked to our website, is not part of this document.

Our results of operations and financial condition can be adversely affected by numerous risks and uncertainties. The most important of these risks and uncertainties are detailed below. You should carefully consider the risk factors detailed below in conjunction with the other information contained in this document. Should any of these risks actually materialize, our business, financial condition, and future prospects could be negatively impacted.

Demand for our services is affected by the economic climate in the industries and markets we serve. The demand for our services, in particular our staffing services, is highly dependent upon the state of economy and upon the staffing needs of our clients. Any negative variation in the economic condition of the United States, United Kingdom or of any of the other foreign countries in which we do business, may severely reduce the demand for our services and thereby significantly decrease our revenues and profits.

Our market is highly competitive with low barriers to entry. Our industry is intensely competitive and highly fragmented, and the barriers to entry are quite low. There are many competitors, and new ones are entering the market constantly. In addition, some of these competitors have greater resources than us. Competition arises locally, regionally, nationally, internationally and in certain cases from remote locations, particularly from offshore locations such as India and China.

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Certain of our contracts are awarded on the basis of competitive proposals, which can be periodically re-bid by the client. There can be no assurance that existing contracts will be renewed on satisfactory terms or that additional or replacement contracts will be awarded to us. In addition, long-term contracts form a negligible portion of our revenue. There can be no assurance we will be able to retain clients or market share in the future. Nor can there be any assurance that we will, in light of competitive pressures, be able to remain profitable or, if profitable, maintain our current profit margins.

Our business requires a qualified candidate pool, which we may not be able to recruit or maintain. Our staffing services consist of the placement of individuals seeking employment in specialized IT and professional positions. Some of these sectors are characterized by a shortage of qualified candidates. There can be no assurance that suitable candidates for employment will continue to be available or will continue to seek employment through us. Candidates generally seek temporary or regular positions through multiple sources, including us and our competitors. Any shortage of qualified candidates could materially adversely affect us.

Our business depends on key personnel, including executive officers, local managers and field personnel. We are engaged in a services business. As such, our success or failure is highly dependent upon the performance of our management personnel and employees, rather than upon technology or upon tangible assets (of which we have few). There can be no assurance that we will be able to attract and retain the personnel that are essential to our success.

We have to comply with existing government regulation and are exposed to increased regulation of the workplace. Our business is subject to regulation or licensing in many states and in certain foreign countries. There can be no assurance we will be able to continue to obtain all necessary licenses or approvals or that the cost of compliance will not prove to be material in the future. Any inability to comply with government regulation or licensing requirements, or increase in the cost of compliance, could materially adversely affect us. Additionally, our staffing services entail employing individuals on a temporary basis and placing such individuals in clients’ workplaces. Increased government regulation of the workplace or of the employer-employee relationship could materially adversely affect us.

We are exposed to claims and costs, liabilities and litigation arising from the delivery of our services. Our recruiting services involve our referring candidates to clients for potential employment, and our staffing services entail employing or retaining individuals on a temporary basis and placing such individuals in clients’ workplaces. Our recruiting services entail a risk of liability to our clients and others, contractually and otherwise, arising from allegations of inadequate background checks, inadequate credentialing of our nursing and healthcare workers, and negligent referral of candidates to our clients. Our staffing services entail a risk of liability to our clients and others, contractually and otherwise, arising from various workplace events, often beyond our control, including allegations of errors and omissions, injury to property or persons, or misappropriation or theft of property or proprietary information allegedly caused or contributed to by our temporary workers. Our staffing services also entail a risk of employment and co-employment liability, to either or both our clients and our temporary workers, arising from allegations by our temporary workers of discrimination, harassment, inadequate workplace conditions, or entitlement to employee benefits or pay from clients to which they are assigned. The Company maintains insurance with respect to many of the aforementioned claims. While such claims have not historically had a material adverse effect upon the Company, there can be no assurance that the Company will continue to be able to obtain insurance at a cost that does not have a material adverse effect upon the Company or that such claims (whether by reason of the Company not having insurance or by reason of such claims being outside the scope of the Company’s insurance) will not have a material adverse effect upon the Company.

We have acquired, and may continue to acquire, companies, and these acquisitions could disrupt our business or adversely affect our earnings. We have acquired several companies and may continue to acquire companies in the future. Entering into an acquisition entails many risks, any of which could harm our business, including failure to successfully integrate the acquired company with our existing business, alienation or impairment of relationships with substantial customers or key employees of the acquired business or our existing

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business, and assumption of liabilities of the acquired business. Any acquisition that we consummate also may have an adverse affect on our liquidity or earnings and may be dilutive to our earnings. Adverse business conditions or developments suffered by or associated with any business we acquire additionally could result in impairment to the goodwill or intangible assets associated with the acquired business, and a related write down of the value of these assets, and adversely affect our earnings.

The price of our common stock may fluctuate significantly. The market price for our common stock can fluctuate as a result of a variety of factors, including the factors listed above, many of which are beyond our control. These factors include: actual or anticipated variations in quarterly operating results; announcements of new services by our competitors or us; announcements relating to strategic relationships or acquisitions; changes in financial estimates or other statements by securities analysts; and other changes in general economic conditions. Because of this, we may fail to meet or exceed the expectations of our shareholders or of our securities analysts, and the market price for our common stock could fluctuate as a result.

There are no unresolved comments from the Staff of the Securities and Exchange Commission concerning our periodic or current reports under the Securities Exchange Act of 1934.

Our corporate headquarters, located in Jacksonville, Florida, is on lease through 2012. Our business services are conducted through more than 190 offices located in the United States, Canada, the United Kingdom, and continental Europe. Almost all of our offices are on lease, with the terms of an average office lease being from three to six years.

We believe our facilities are generally adequate for our needs and do not anticipate difficulty replacing such facilities or locating additional facilities, if needed. Additional information on lease commitments can be found in Footnote 6 to the Consolidated Financial Statements.

We are a party to a number of lawsuits and claims arising out of the ordinary conduct of our business. In the opinion of management, based on the advice of in-house and external legal counsel, the lawsuits and claims pending are not likely to have a material adverse effect on us, our financial position, our results of operations, or our cash flows.

No matters were submitted to a vote of security holders during the fourth quarter of 2005.

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PART II

Market Price and Related Matters

The following table sets forth the high and low sale prices of our Common Stock, as reported by the NYSE, during the two years ended December 31, 2005:

See the factors set forth above in ‘Risk Factors,’ for factors that may impact the price of our Common Stock. As of March 1, 2006, there were approximately 859 holders of record of our Common Stock.

We have not paid to-date a cash dividend or other cash distribution with respect to our Common Stock. We currently intend to retain any earnings to provide for the operation and expansion of our business and do not anticipate paying any cash dividends in the foreseeable future.

Issuer Repurchases of Equity Securities

Our Board of Directors has authorized the repurchase of our Common Stock, comprised of an initial $65 million authorization and an additional $65 million authorization in the second quarter of 2005. From inception through the year-end of 2005, approximately 8.8 million shares at a cost of $77.2 million have been repurchased under this authorization. The following table sets forth information about our Common Stock repurchases for the three months ended December 31, 2005. We have repurchased 457,000 shares at a cost of $6.5 million in 2006, which brought the total amount repurchased under this plan to 9.3 million shares at a cost of $83.7 million at March 1, 2006. We anticipate that we will continue to purchase shares under this authorization in the future. There is no expiration date for this authorization.

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