# Professional services firms headquartered in Overijssel
Tamtam tracks 34 professional services firms headquartered in Overijssel. This list ranks all of them by number of employees on LinkedIn, led by Witteveen+Bos, VIRO and TAUW Nederland. Their median headcount is 152. Half of them were founded in 1996 or later. The most common headquarters are Zwolle (9), Deventer (7) and Enschede (7).
The professional services firms in Overijssel are a mix of engineering, environmental, and financial services companies. Witteveen+Bos is a global engineering and consultancy firm, TAUW Nederland focuses on environmental solutions, and Moore MKW provides accounting and advisory services. Other notable firms include Optica, specializing in coaching and training, and Countus, another accounting and advisory organization.
These firms are predominantly mid-sized to large, with several established decades ago, such as TAUW Nederland (1928) and Countus (1924). There is a clear concentration of headquarters in Deventer and Zwolle, indicating these cities as significant hubs for professional services within Overijssel.
π³π± Overijssel Β· 34 companies Β· Updated Nov 11, 2026
| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Witteveen+Bos](https://www.tamtam.ai/c/witteveen-bos) (witteveenbos.com)
Global engineering and consultancy firm providing sustainable solutions in infrastructure, water, environment, and construction projects worldwide with a focus on value creation and talent development | Civil Engineering | π³π± Deventer | 1,892 | |
| 2 | [VIRO](https://www.tamtam.ai/c/viro) (viro-group.com)
Innovative engineering firm specializing in project management and engineering solutions for various industries, enabling clients to achieve their ambitions | Engineering Services | π³π± Hengelo | 983 | 1968 |
| 3 | [TAUW Nederland](https://www.tamtam.ai/c/tauw-nederland) (tauw.nl)
The company shapes a vital living environment by offering meaningful solutions through strong expertise and valuable partnerships | Environmental Services | π³π± Deventer | 840 | 1928 |
| 4 | [Moore MKW](https://www.tamtam.ai/c/moore-mkw) (moore-mkw.nl)
Moore MKW is a forward-thinking accounting and advisory organization focused on personal happiness, business success, and societal contribution through teamwork and innovation | Financial Services | π³π± Zwolle | 769 | 2023 |
| 5 | [Optica](https://www.tamtam.ai/c/optica-zwolle) (optica.nl)
A national coaching and training agency specializing in reintegration and career guidance, guiding clients through seven steps towards sustainable re-entry into the job market | Professional Training and Coaching | π³π± Zwolle | 766 | 2008 |
| 6 | [Jobcenter](https://www.tamtam.ai/c/jobcenter) (jobcenter.nu)
A company specializing in personnel solutions for businesses by providing staffing services in various industries with a focus on quality and problem-solving | Staffing and Recruiting | π³π± Deventer | 689 | 1998 |
| 7 | [Countus](https://www.tamtam.ai/c/countus) (countus.nl)
Countus is an accounting and advisory organization focused on achieving sustainable success for clients, employees, and stakeholders through a wide range of services | Accounting | π³π± Zwolle | 595 | 1924 |
| 8 | [Demcon](https://www.tamtam.ai/c/demcon) (demcon.com)
Develops, prototypes, industrializes, and manufactures high-quality, innovative, and complex systems and products, integrating various engineering fields to solve societal and technological challenges. | Engineering Services | π³π± Enschede | 487 | 1993 |
| 9 | [Aveco de Bondt](https://www.tamtam.ai/c/aveco-de-bondt) (avecodebondt.nl)
Aveco de Bondt is a medium-sized, independent engineering company specializing in comprehensive solutions for construction, infrastructure, space, and environment with experienced specialists | Civil Engineering | π³π± Holten | 459 | 1969 |
| 10 | [Indes](https://www.tamtam.ai/c/indes) (indes.eu)
Creating successful innovations in Medical Cure, Human Care, and E-mobility by delivering integrated product solutions that improve everyday life | Medical Equipment Manufacturing | π³π± Enschede | 317 | 1988 |
| 11 | [Goudappel](https://www.tamtam.ai/c/goudappel) (goudappel.nl)
Assists clients making sustainable mobility choices with over 250 diverse experts from traffic consultants to landscape architects, fostering collaboration and diversity. | Business Consulting and Services | π³π± Deventer | 315 | 1963 |
| 12 | [Eshuis Accountants en Adviseurs](https://www.tamtam.ai/c/eshuis-accountants-en-adviseurs) (eshuis.com)
A full-service accounting and tax advisory firm catering to small to medium-sized businesses in Eastern Netherlands Specializing in construction, technology, healthcare sectors | Financial Services | π³π± Almelo | 309 | 1932 |
| 13 | [Global Talk](https://www.tamtam.ai/c/global-talk) (globaltalk.nl)
Global Talk is an organization of 2000 interpreters and cultural specialists, speaking over 200 languages, facilitating communication in various important settings across the Netherlands | Translation and Localization | π³π± Hengelo | 295 | 1976 |
| 14 | [IJssel Technology Services](https://www.tamtam.ai/c/ijssel-technology-services) (ijssel.com)
Experts in production improvement, offering smart solutions for quick and efficient product development One-stop shop for production, installation, implementation, and maintenance | Industrial Machinery Manufacturing | π³π± Zwolle | 268 | 1992 |
| 15 | [DamstΓ© lawyers β civil law notaries](https://www.tamtam.ai/c/damste-lawyers-civil-law-notaries) (damste.nl)
A prominent firm providing legal advice and services in civil law for businesses, institutions, governments, and individuals in the Twente region | Law Practice | π³π± Enschede | 193 | 1947 |
| 16 | [In Person](https://www.tamtam.ai/c/in-person) (inperson.nl)
Specializing in flexible staffing, we prioritize customer and employee happiness With over 20,000 flexible workers, we help clients excel and grow | Human Resources Services | π³π± Enschede | 190 | |
| 17 | [Ignite Group Nederland](https://www.tamtam.ai/c/ignite-group-nederland) (ignite-group.com)
Vindsubsidies is a full-service subsidy consultancy with extensive experience in optimizing subsidies for businesses and projects across various industries and sectors | Business Consulting and Services | π³π± Deventer | 152 | 1997 |
| 18 | [Brouwers Accountants & Adviseurs](https://www.tamtam.ai/c/brouwers-accountants-and-adviseurs) (brouwers.nl)
A dynamic accounting and advisory firm offering multidisciplinary expertise, a strong network, and a focus on entrepreneurial success for clients and staff | Financial Services | π³π± Zwolle | 139 | |
| 19 | [KroeseWevers](https://www.tamtam.ai/c/kroesewevers) (moore-mkw.nl)
Multidisciplinary firm in the Netherlands offering personalized accounting, tax, and financial services to diverse entrepreneurial clients, promoting growth and improvement | Financial Services | π³π± Enschede | 112 | 1979 |
| 20 | [FACTO GEO](https://www.tamtam.ai/c/facto-geo) (facto-geo.nl)
This company provides geodesic engineering services and geodata processing, including land surveying, GIS updates, 3D modeling, and measurements for various construction and infrastructure projects. | Civil Engineering | π³π± Deventer | 100 | 1996 |
| 21 | [SMK Accountants & Fiscalisten](https://www.tamtam.ai/c/smk-accountants-and-fiscalisten) (smkaccountants.nl)
The company provides comprehensive accounting services, including administration, auditing, tax advice, and online services, focusing on building long-term relationships and delivering added value | Financial Services | π³π± Enschede | 99 | |
| 22 | [CMC Worldwide](https://www.tamtam.ai/c/cmc-worldwide) (cmcww.com)
Credit management company focused on collecting overdue invoices, preventing future delays, and providing tailored services for SMEs and multinational corporations worldwide | Financial Services | π³π± Zwolle | 64 | 2011 |
| 23 | [ROZ Groep](https://www.tamtam.ai/c/roz-groep) (rozondernemerspunt.nl)
Providing support to entrepreneurs in Twente and Achterhoek with advice, coaching, training, financing, and debt relief, since 2005 Encouraging social impact entrepreneurship | Financial Services | π³π± Hengelo | 57 | 2005 |
| 24 | [Eurofins \| MASER](https://www.tamtam.ai/c/eurofins-maser) (maserengineering.eu)
An independent engineering service company specializing in reliability testing and failure analysis for semiconductor and electronic systems in various industries | Semiconductor Manufacturing | π³π± Enschede | 45 | 1993 |
| 25 | [Horequip](https://www.tamtam.ai/c/horequip) (horequip.com)
A specialist in designing, consulting, managing projects, supplying, and building food service areas, with a focus on creating great guest experiences and functionality | Restaurants | π³π± Steenwijk | 38 | 1989 |
| 26 | [Blue-Y](https://www.tamtam.ai/c/blue-y) (blue-y.com)
Result-oriented advisors in healthcare specializing in implementing technology for future care improvements | IT Services and IT Consulting | π³π± Hengelo | 32 | 2017 |
| 27 | [Epartment \| Commerce experts.](https://www.tamtam.ai/c/epartment-commerce-experts) (epartment.nl)
Innovative e-commerce organization with expertise in marketing, IT, finance systems, design, and technology, delivering tailored solutions for webshops and SAP/Accountview integration | Technology, Information and Internet | π³π± Hengelo | 26 | 2014 |
| 28 | [ABC Pensioen](https://www.tamtam.ai/c/abc-pensioen) (abcpensioen.nl)
ABC Pensioen specializes in advising, managing, and communicating pension plans for employers, entrepreneurs, and individuals, ensuring financial security for the future | Financial Services | π³π± Hardenberg | 14 | 2011 |
| 29 | [EAVS](https://www.tamtam.ai/c/eavs) (eavs.nl)
A company specializing in audiovisual installations for the cultural and corporate sectors, focusing on aesthetic outcomes, user-friendly design, and creative solutions within budget constraints | Entertainment Providers | π³π± Basse | 10 | 2020 |
| 30 | [OC](https://www.tamtam.ai/c/oc) (olavcoaching.com)
This company focuses on facilitating personal growth, self-discovery, and achieving goals through coaching based on empathy, intrinsic change, and individualized support | Professional Training and Coaching | π³π± Zwolle | 9 | 2016 |
| 31 | [Flireo B.V.](https://www.tamtam.ai/c/flireo-b-v) (flireo.nl)
Flireo specializes in creating AI solutions to exceed expectations, born from expertise and driven by challenges to unlock growth potential with a commitment to excellence | IT System Custom Software Development | π³π± Deventer | 5 | 2023 |
| 32 | [ProMa Consulting B.V.](https://www.tamtam.ai/c/proma-consulting-b-v) (proma-consulting.nl)
ProMa Consulting is an organizational consultancy firm specializing in project and organizational control, policy implementation, quality audits, and specialist teams for various industries | Business Consulting and Services | π³π± Vriezenveen | 4 | 2010 |
| 33 | [Zorgadviseurs.nl](https://www.tamtam.ai/c/zorgadviseurs-nl) (zorgadviseurs.nl)
An association of experienced healthcare professionals focused on innovating and improving healthcare by connecting different sectors and implementing new care concepts | Hospitals and Health Care | π³π± Zwolle | 3 | |
| 34 | [Exante.ai](https://www.tamtam.ai/c/exante-ai) (exante-ai.nl)
Specialized in artificial intelligence and data science, we help organizations develop AI strategies, conduct research, provide data-driven advice, and build agile AI teams | IT Services and IT Consulting | π³π± Zwolle | 1 | 2020 |
## 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.
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Source: https://www.tamtam.ai/l/professional-services-firms-overijssel