# 30 leading professional services firms in Brussels
Tamtam tracks 64 professional services firms headquartered in Brussels. This list ranks the 30 largest by number of employees on LinkedIn, led by BDO, Akka Technologies and TRACTEBEL. Their median headcount is 525. Half of them were founded in 1992 or later.
This selection of professional services firms in Brussels includes large consultancies and specialized engineering companies. The companies listed are primarily large groups, with several thousand employees each, serving a global clientele.
BDO, with over 50,000 employees, offers accounting services. Akka Technologies provides engineering and R&D services, while TRACTEBEL specializes in sustainable energy and built environment projects. Arthur D. Little focuses on strategic consulting. The data indicates a concentration of large, established firms in the professional services sector, with a strong presence in engineering and consulting.
๐ง๐ช Brussels ยท 30 companies ยท Updated Nov 11, 2026
| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [BDO](https://www.tamtam.ai/c/bdo-brussels) (bdo.global)
Providing professional services globally with 1800 offices, focusing on quality, technology, and innovative solutions for long-term client value. | Accounting | ๐ง๐ช Brussels | 51,974 | |
| 2 | [Akka Technologies](https://www.tamtam.ai/c/akka-technologies) (akkodis.com)
European leader in engineering consulting and R&D services, supporting clients with digital solutions and expertise across various sectors throughout product life cycles. | IT Services and IT Consulting | ๐ง๐ช Brussels | 7,700 | 1984 |
| 3 | [TRACTEBEL](https://www.tamtam.ai/c/tractebel) (tractebel-engie.com)
Provides integrated solutions for sustainable energy and built environment projects, offering expertise in nuclear, renewables, power, grids, infrastructure, and water resources. | Engineering Services | ๐ง๐ช Brussels | 7,185 | |
| 4 | [Equans BeLux](https://www.tamtam.ai/c/equans-belux) (equans.be)
The company focuses on solving challenges by creating smarter cities, efficient industries, and sustainable buildings through a range of expertise and services | Industrial Machinery Manufacturing | ๐ง๐ช Brussels | 4,917 | |
| 5 | [TPF](https://www.tamtam.ai/c/tpf) (tpfgroup.com)
Global multidisciplinary engineering consultancy providing end-to-end project execution across fifty countries using local know-how and international expertise for diverse infrastructure and development sectors. | Civil Engineering | ๐ง๐ช Brussels | 4,569 | |
| 6 | [Arthur D. Little](https://www.tamtam.ai/c/arthur-d-little) (adlittle.com)
Providing creative and scientific solutions, we help clients anticipate change, innovate through technology and strategy, and make a positive impact globally | Business Consulting and Services | ๐ง๐ช Brussels | 2,467 | 1886 |
| 7 | [Marsh Europe](https://www.tamtam.ai/c/marsh-europe) (marsh.com)
Global leader in insurance brokerage and risk advisory services, offering data-driven solutions for commercial and individual clients worldwide Operating in 130+ countries | Professional Services | ๐ง๐ช Brussels | 1,682 | |
| 8 | [Partena Professional](https://www.tamtam.ai/c/partena-professional) (partena-professional.be)
A service provider specializing in entrepreneurship and personnel management, offering support in administrative procedures, HR policy, legal advice, and consultancy services | Human Resources Services | ๐ง๐ช Brussels | 1,535 | |
| 9 | [Moore Belgium](https://www.tamtam.ai/c/moore-belgium) (moore.be)
Leading independent accounting and consulting firm in Belgium helping entrepreneurs achieve their goals through a wide range of services including tax, audit, finance, and business consulting | Business Consulting and Services | ๐ง๐ช Brussels | 1,350 | |
| 10 | [Mercer Europe](https://www.tamtam.ai/c/mercer-europe) (corporate.marsh.com)
Dedicated to providing advisory services and technological solutions to help organizations meet workforce health, investment, and career needs Operating in multiple countries | Professional Services | ๐ง๐ช Brussels | 1,235 | 1993 |
| 11 | [Mensura](https://www.tamtam.ai/c/mensura) (mensura.be)
Specializing in workplace prevention and health promotion, this team offers expert advice and personalized solutions to help maintain a productive and compliant workforce | Human Resources Services | ๐ง๐ช Brussels | 867 | 2006 |
| 12 | [Stibbe](https://www.tamtam.ai/c/stibbe) (stibbe.com)
A leading independent international law firm providing high-quality legal advice, transactions, and litigation services to a diverse range of clients globally | Law Practice | ๐ง๐ช Brussels | 840 | 1911 |
| 13 | [TUC RAIL](https://www.tamtam.ai/c/tuc-rail) (tucrail.be)
Specialized engineering company providing innovative, sustainable railway technology and infrastructure solutions with multidisciplinary expertise for projects in Belgium and internationally. | Civil Engineering | ๐ง๐ช Brussels | 760 | 1992 |
| 14 | [CBTW IT & Technology / Positive Thinking Company](https://www.tamtam.ai/c/cbtw-it-and-technology-positive-thinking-company) (cbtw.tech)
Providing comprehensive technology solutions including software engineering, security, cloud, data analytics, and digital workplace through a global delivery model. | IT Services and IT Consulting | ๐ง๐ช Brussels | 644 | |
| 15 | [SECO Group](https://www.tamtam.ai/c/seco-group) (groupseco.com)
A leading provider of technical risk prevention, quality supervision, and inspection services for construction projects, supporting innovation and sustainability | Construction | ๐ง๐ช Brussels | 525 | |
| 16 | [Amrop](https://www.tamtam.ai/c/amrop) (amrop.com)
Global executive search firm providing leadership and board services across 55 countries, with a context-driven approach to identifying and positioning top talent worldwide | Business Consulting and Services | ๐ง๐ช Brussels | 518 | 1977 |
| 17 | [Express Medical](https://www.tamtam.ai/c/express-medical) (expressmedical.be)
Specializing in recruitment and selection of nursing and paramedical staff since 1988, our company partners with healthcare facilities to provide staffing solutions based on partnership, professionalism, and passion | Staffing and Recruiting | ๐ง๐ช Brussels | 441 | 1988 |
| 18 | [Cronos Europa](https://www.tamtam.ai/c/cronos-europa) (cronoseuropa.com)
Providing IT and digital communication solutions to European institutions, leveraging advanced technologies and extensive expertise across multiple countries. | Professional Services | ๐ง๐ช Brussels | 430 | 2005 |
| 19 | [ESN](https://www.tamtam.ai/c/esn-brussels) (esn.eu)
Leading communications agency and information provider in Brussels, offering media services, business consultancy, events management, and translation services with creativity and technology | Public Relations and Communications Services | ๐ง๐ช Brussels | 395 | 1986 |
| 20 | [IBF Expertise](https://www.tamtam.ai/c/ibf-expertise) (ibf.be)
Consultancy services for international development projects focusing on economic growth, trade, education, social reforms, and institutional support in emerging economies. | International Affairs | ๐ง๐ช Brussels | 380 | 1977 |
| 21 | [JONCKERS](https://www.tamtam.ai/c/jonckers) (acclaro.com)
The company provides quality translation and localization services since 1994 Their platform, WordsOnline, offers AI-powered translation solutions for global businesses | Translation and Localization | ๐ง๐ช Brussels | 368 | 1994 |
| 22 | [Intys](https://www.tamtam.ai/c/intys) (intys.eu)
Support organizations in Belgium across various sectors with project management, business transformation, and operational excellence consulting services. | Business Consulting and Services | ๐ง๐ช Brussels | 365 | 2007 |
| 23 | [NVISO Security](https://www.tamtam.ai/c/nviso-security) (nviso.eu)
Provides cyber security services using skilled professionals, preventing and detecting security challenges for clients with positive business outcomes. | Computer and Network Security | ๐ง๐ช Brussels | 348 | 2013 |
| 24 | [Transurb](https://www.tamtam.ai/c/transurb) (transurb.com)
Specializes in bespoke rail simulation and advanced training solutions, alongside technical assistance and project management in rail and urban mobility. | Rail Transportation | ๐ง๐ช Brussels | 343 | 1973 |
| 25 | [Eurofins Consumer Products Assurance](https://www.tamtam.ai/c/eurofins-consumer-products-assurance) (eurofins.com)
Global network providing supply chain assurance and quality services to various industries, supporting compliance, risk mitigation, brand protection, and customer satisfaction | International Trade and Development | ๐ง๐ช Brussels | 292 | 2005 |
| 26 | [Gevers](https://www.tamtam.ai/c/gevers) (gevers.eu)
European leader in Intellectual Property services with 120+ years experience Specializing in trademark and patent prosecution, serving international clients including China | Legal Services | ๐ง๐ช Brussels | 268 | 1898 |
| 27 | [GOPA PACE](https://www.tamtam.ai/c/gopa-pace) (gopa.eu)
Global consulting firm specializing in international and bilateral projects focused on societal transformation and sustainable development since 1991. | Business Consulting and Services | ๐ง๐ช Brussels | 262 | |
| 28 | [Contraste Europe](https://www.tamtam.ai/c/contraste-europe) (contraste.com)
A leading IT services group with expertise in IT advisory, data intelligence, digital services, cloud platforms, ERP, and support services for various sectors | IT Services and IT Consulting | ๐ง๐ช Brussels | 259 | 1994 |
| 29 | [Forvis Mazars in Belgium](https://www.tamtam.ai/c/forvis-mazars-in-belgium) (forvismazars.com)
Innovative, multi-disciplinary firm offering audit, accounting, tax, and advisory services with personalized solutions and a focus on client needs | Financial Services | ๐ง๐ช Brussels | 253 | |
| 30 | [element61](https://www.tamtam.ai/c/element61) (element61.be)
Industry-leading consulting company in Belgium specializing in Business Analytics, Data Science, and Performance Management, with a focus on professional development and team collaboration | IT Services and IT Consulting | ๐ง๐ช Brussels | 149 | 2007 |
## How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 11, 2026.
## More company lists in Brussels
- [The largest companies in Brussels](https://www.tamtam.ai/l/largest-companies-brussels) (1,033)
- [Multinational companies in Brussels](https://www.tamtam.ai/l/multinational-companies-brussels) (326)
- [Financial services firms in Brussels](https://www.tamtam.ai/l/financial-services-firms-brussels) (96)
- [Public sector organisations in Brussels](https://www.tamtam.ai/l/public-sector-organisations-brussels) (79)
- [IT Services and IT Consulting companies in Brussels](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-brussels) (75)
- [Retail chains in Brussels](https://www.tamtam.ai/l/retail-chains-brussels) (71)
- [Critical infrastructure operators in Brussels](https://www.tamtam.ai/l/critical-infrastructure-operators-brussels) (70)
- [IT services companies in Brussels](https://www.tamtam.ai/l/it-services-companies-brussels) (63)
- [Companies with in-house R&D in Brussels](https://www.tamtam.ai/l/r-and-d-companies-brussels) (60)
- [Financial Services companies in Brussels](https://www.tamtam.ai/l/financial-services-companies-brussels) (54)
- [SaaS companies in Brussels](https://www.tamtam.ai/l/saas-companies-brussels) (54)
- [Consulting firms in Brussels](https://www.tamtam.ai/l/consulting-firms-brussels) (52)
- [Government Administration companies in Brussels](https://www.tamtam.ai/l/government-administration-companies-brussels) (52)
- [Insurance companies in Brussels](https://www.tamtam.ai/l/insurance-companies-brussels) (49)
- [Software Development companies in Brussels](https://www.tamtam.ai/l/software-development-companies-brussels) (47)
- [Companies with a mobile app in Brussels](https://www.tamtam.ai/l/companies-with-mobile-app-brussels) (42)
- [Education providers in Brussels](https://www.tamtam.ai/l/education-companies-brussels) (38)
- [Non-profit Organizations companies in Brussels](https://www.tamtam.ai/l/non-profit-organizations-companies-brussels) (38)
- [Subscription businesses in Brussels](https://www.tamtam.ai/l/subscription-businesses-brussels) (38)
- [Advertising Services companies in Brussels](https://www.tamtam.ai/l/advertising-services-companies-brussels) (34)
- [Marketing and communications agencies in Brussels](https://www.tamtam.ai/l/marketing-agencies-brussels) (33)
- [Hotel and hospitality groups in Brussels](https://www.tamtam.ai/l/hospitality-groups-brussels) (31)
- [Manufacturers in Brussels](https://www.tamtam.ai/l/manufacturers-brussels) (30)
- [Recruitment and staffing agencies in Brussels](https://www.tamtam.ai/l/recruitment-agencies-brussels) (29)
## The same list elsewhere in Belgium
- [Professional services firms in Belgium](https://www.tamtam.ai/l/professional-services-firms-belgium) (396)
- [Professional services firms in Flanders](https://www.tamtam.ai/l/professional-services-firms-flanders) (263)
- [Professional services firms in Wallonia](https://www.tamtam.ai/l/professional-services-firms-wallonia) (38)
- [Professional services firms in Antwerp](https://www.tamtam.ai/l/professional-services-firms-antwerp) (49)
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Source: https://www.tamtam.ai/l/professional-services-firms-brussels