# The 30 largest consulting firms in Istanbul

Tamtam tracks 34 consulting firms headquartered in Istanbul. This list ranks the 30 largest by number of employees on LinkedIn, led by KUCUKYiLMAZ Consulting Co., Innova and KPMG Türkiye. Their median headcount is 400. Half of them were founded in 2004 or later.

The consulting firms in Istanbul featured here are mostly large companies, with headcounts ranging from around 400 to over 2,300 employees. Many specialize in IT services and consulting, such as Innova, which provides IT solutions, and BGTS, an international technology consulting firm. Other firms, like KPMG Türkiye, offer audit, tax, and advisory services across various industries.

A common thread among these companies is their focus on digital transformation and technology. OBSS specializes in technology consulting for a cloud-powered future, while adesso Turkey offers custom software development and IT solutions. KUCUKYiLMAZ Consulting Co., with its focus on the friction industry, stands out as a more specialized consultancy, while YKS focuses on sectoral informing in facilities and property management.

🇹🇷 Istanbul · 30 companies · Updated Nov 12, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [KUCUKYiLMAZ Consulting Co.](https://www.tamtam.ai/c/kucukyilmaz-consulting-co) (facebook.com)<br>With 25 years of experience in the friction industry, offering assistance in compounding, process, product, and business development, representing major suppliers | Motor Vehicle Manufacturing | 🇹🇷 Istanbul | 2,363 | 2004 |
| 2 | [Innova](https://www.tamtam.ai/c/innova-istanbul) (innova.com.tr)<br>Leading Turkish IT solutions provider with 1400 professionals offering platform-independent solutions in various sectors, exporting solutions to 33 countries across 3 continents | IT Services and IT Consulting | 🇹🇷 Istanbul | 2,115 | 1999 |
| 3 | [KPMG Türkiye](https://www.tamtam.ai/c/kpmg-turkiye) (kpmg.com)<br>Providing audit, tax, and advisory services to diverse industries with a sector-focused approach and extensive local and international expertise. | Business Consulting and Services | 🇹🇷 Istanbul | 1,446 | 1982 |
| 4 | [BGTS](https://www.tamtam.ai/c/bgts) (bilgeadam.com)<br>An international technology consulting firm specializing in software development, IT consulting, business processes, QA & testing, big data, cloud, AI/ML, and cybersecurity services | IT Services and IT Consulting | 🇹🇷 Istanbul | 1,182 | 1997 |
| 5 | [OBSS](https://www.tamtam.ai/c/obss) (obss.tech)<br>Leader in technology consulting for a cloud-powered future, with expertise in banking, insurance, e-commerce, retail, and start-ups Strong team with offices in Europe | IT Services and IT Consulting | 🇹🇷 Istanbul | 870 | 2005 |
| 6 | [Özel bir danışmanlık şirketi](https://www.tamtam.ai/c/ozel-bir-dan-smanl-k-sirketi) (kml.com.tr)<br>Strategic planning, brand management, marketing, sales management, R&D, innovation, HR, supply chain, quality management, IT, corporate governance, digital transformation, corporate training | Business Consulting and Services | 🇹🇷 Istanbul | 705 | 2019 |
| 7 | [DIP](https://www.tamtam.ai/c/dip) (dip.com)<br>Specializing in Data & Analytics solutions, creating custom solutions for organizations, providing consulting services in data transformation, analysis, and management processes | IT Services and IT Consulting | 🇹🇷 Istanbul | 702 | 2012 |
| 8 | [adesso Turkey](https://www.tamtam.ai/c/adesso-turkey) (adesso.com.tr)<br>A digital transformation company with agile beliefs, employing over 10,000 people worldwide, offering custom software development and IT solutions | IT Services and IT Consulting | 🇹🇷 Istanbul | 628 | 2013 |
| 9 | [Commencis](https://www.tamtam.ai/c/commencis) (commencis.com)<br>A company specializing in experience design, software engineering, and cloud technologies, enabling enterprises to build digital experiences and strengthen customer relationships globally | Software Development | 🇹🇷 Istanbul | 542 | 2000 |
| 10 | [Academy](https://www.tamtam.ai/c/academy) (inkaik.com)<br>Specializing in HR research, selection, project-based staffing, HR consultancy, management consultancy, and payroll services with a focus on professionalism and confidentiality | Human Resources Services | 🇹🇷 Istanbul | 537 |  |
| 11 | [Testinium](https://www.tamtam.ai/c/testinium) (testinium.com)<br>Innovative team providing software consulting, test outsourcing, and training services with expertise in various testing approaches and frameworks | IT Services and IT Consulting | 🇹🇷 Istanbul | 492 | 2010 |
| 12 | [Detaysoft](https://www.tamtam.ai/c/detaysoft) (detaysoft.com)<br>Leader in SAP solutions, driving digital transformation through R&D, expert consultants, and global partnerships Trusted by 300+ clients with 1000+ successful projects worldwide | Software Development | 🇹🇷 Istanbul | 444 | 1999 |
| 13 | [BDO Türkiye](https://www.tamtam.ai/c/bdo-turkiye) (bdo.com.tr)<br>An audit and consultancy organization providing professional services in Audit & Assurance, Tax, Social Security, Accounting, and Advisory across the globe | Accounting | 🇹🇷 Istanbul | 414 | 1981 |
| 14 | [DefineX](https://www.tamtam.ai/c/definex) (teamdefinex.com)<br>A forward-thinking consulting house and venture builder focused on digital acceleration, innovation, and cultivating talent for the success of tomorrow | Business Consulting and Services | 🇹🇷 Istanbul | 405 | 2019 |
| 15 | [YKS](https://www.tamtam.ai/c/yks) (yks.com.tr)<br>Specializing in sectoral informing, our team expands knowledge in facilities and property management, offering reports and services in energy, waste, security, and more | Business Consulting and Services | 🇹🇷 Istanbul | 400 | 1988 |
| 16 | [KoçZer](https://www.tamtam.ai/c/koczer) (koczer.com)<br>Leader in procurement & supply chain management with 20+ years of experience, providing end-to-end solutions, strategic roadmaps, mass purchases, and technological solutions | Business Consulting and Services | 🇹🇷 Istanbul | 390 | 2003 |
| 17 | [Nagarro + MBIS](https://www.tamtam.ai/c/nagarro-mbis) (nagarro.com.tr)<br>Leading digital engineering and consulting firm offering innovative solutions for digital transformation, specializing in SAP services for global markets | IT Services and IT Consulting | 🇹🇷 Istanbul | 369 | 2000 |
| 18 | [Sistem Global Danışmanlık A.Ş.](https://www.tamtam.ai/c/sistem-global-dan-smanl-k-a-s) (sistemglobal.com.tr)<br>Provider of financial, legal, and consultancy services for technology companies, specializing in corporate finance, tax, audit, patents, and international funds | Business Consulting and Services | 🇹🇷 Istanbul | 368 | 1996 |
| 19 | [E Mali Müşavirlik](https://www.tamtam.ai/c/e-mali-musavirlik) (emusavirlik.com)<br>Specializing in advisory services in Mali, providing expert guidance and consulting solutions to clients | Financial Services | 🇹🇷 Istanbul | 345 | 2015 |
| 20 | [Forvis Mazars Türkiye](https://www.tamtam.ai/c/forvis-mazars-turkiye) (forvismazars.com)<br>Global professional services firm serving over 1,500 companies worldwide with a team of 350+ professionals across multiple offices, committed to highest standards and ethics | Accounting | 🇹🇷 Istanbul | 334 | 1977 |
| 21 | [FEV Türkiye](https://www.tamtam.ai/c/fev-turkiye) (fev.com)<br>A provider of turnkey engineering solutions in the automotive industry, specializing in vehicle development, software, autonomous driving, and propulsion systems | Motor Vehicle Manufacturing | 🇹🇷 Istanbul | 330 | 2011 |
| 22 | [Solvia Digital Solutions](https://www.tamtam.ai/c/solvia-digital-solutions) (solviads.com)<br>Design, integrate, and optimize SAP and IT solutions to enhance agility, resilience, and long-term digital transformation for businesses. | IT Services and IT Consulting | 🇹🇷 Istanbul | 318 | 2014 |
| 23 | [RİSUS INTERNATIONAL](https://www.tamtam.ai/c/risus-international) (risusinternational.com)<br>Specializing in change management, analysis, and training services to improve organizational performance through customized solutions and development programs | Human Resources Services | 🇹🇷 Istanbul | 244 | 2006 |
| 24 | [VİZYON](https://www.tamtam.ai/c/vizyon) (vizyongrubu.com)<br>Specializing in tax, auditing, and consulting services to provide comprehensive financial guidance and support to clients | Financial Services | 🇹🇷 Istanbul | 233 | 1984 |
| 25 | [Odine](https://www.tamtam.ai/c/odine) (odine.com)<br>Global telecom partner enabling sustainable network transformation with resilient, software-defined networks Offers communication solutions and collaborative partnerships to support evolving telecom companies | IT Services and IT Consulting | 🇹🇷 Istanbul | 205 | 2000 |
| 26 | [Caretta](https://www.tamtam.ai/c/caretta) (caretta.net)<br>A software company offering custom development, IT consultancy, and outsourcing services, specializing in solutions for the pharmaceutical sector, with global quality standards | Software Development | 🇹🇷 Istanbul | 186 | 1997 |
| 27 | [GoLive Yazılım A.Ş](https://www.tamtam.ai/c/golive-yaz-l-m-a-s) (golive.com.tr)<br>Specializes in SAP ERP implementation and SAP S/4HANA transformation projects, providing expert consultancy, support, and solutions for digital transformation in all industries | IT Services and IT Consulting | 🇹🇷 Istanbul | 185 | 2012 |
| 28 | [MDP Group](https://www.tamtam.ai/c/mdp-group) (mdpgroup.com)<br>A provider of SAP consulting and development services, specializing in digital transformation, e-Transformation, web/mobile app development, and ongoing R&D in FinTech and data analytics | IT Services and IT Consulting | 🇹🇷 Istanbul | 149 | 2013 |
| 29 | [Experilabs (SahaBT Yazılım)](https://www.tamtam.ai/c/experilabs-sahabt-yaz-l-m) (experilabs.com)<br>Providing tailored solutions for corporate clients through consulting, training, outsourcing, test automation, and expertise in software solutions, Java, RPA, Devops, and project management | Software Development | 🇹🇷 Istanbul | 117 | 2009 |
| 30 | [VBM](https://www.tamtam.ai/c/vbm) (vbm.com.tr)<br>Innovative consultancy specializing in Uipath RPA, Test Automation, Document Understanding, offering software development services, UiPath training, and global support | IT Services and IT Consulting | 🇹🇷 Istanbul | 112 | 2015 |

## 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 12, 2026.

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Source: https://www.tamtam.ai/l/consulting-firms-istanbul