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.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
KUCUKYiLMAZ Consulting Co.facebook.com
With 25 years of experience in the friction industry, offering assistance in compounding, process, product, and business development, representing major suppliers |
2,363 | |||
| 2 |
Innovainnova.com.tr
Leading Turkish IT solutions provider with 1400 professionals offering platform-independent solutions in various sectors, exporting solutions to 33 countries across 3 continents |
2,115 | |||
| 3 |
KPMG Türkiyekpmg.com
Providing audit, tax, and advisory services to diverse industries with a sector-focused approach and extensive local and international expertise. |
1,446 | |||
| 4 |
BGTSbilgeadam.com
An international technology consulting firm specializing in software development, IT consulting, business processes, QA & testing, big data, cloud, AI/ML, and cybersecurity services |
1,182 | |||
| 5 | 870 | ||||
| 6 |
Özel bir danışmanlık şirketikml.com.tr
Strategic planning, brand management, marketing, sales management, R&D, innovation, HR, supply chain, quality management, IT, corporate governance, digital transformation, corporate training |
705 | |||
| 7 | 702 | ||||
| 8 |
adesso Turkeyadesso.com.tr
A digital transformation company with agile beliefs, employing over 10,000 people worldwide, offering custom software development and IT solutions |
628 | |||
| 9 |
Commenciscommencis.com
A company specializing in experience design, software engineering, and cloud technologies, enabling enterprises to build digital experiences and strengthen customer relationships globally |
542 | |||
| 10 | 
Academyinkaik.com
Specializing in HR research, selection, project-based staffing, HR consultancy, management consultancy, and payroll services with a focus on professionalism and confidentiality |
537 | |||
| 11 |
Testiniumtestinium.com
Innovative team providing software consulting, test outsourcing, and training services with expertise in various testing approaches and frameworks |
492 | |||
| 12 |
Detaysoftdetaysoft.com
Leader in SAP solutions, driving digital transformation through R&D, expert consultants, and global partnerships Trusted by 300+ clients with 1000+ successful projects worldwide |
444 | |||
| 13 |
BDO Türkiyebdo.com.tr
An audit and consultancy organization providing professional services in Audit & Assurance, Tax, Social Security, Accounting, and Advisory across the globe |
414 | |||
| 14 |
DefineXteamdefinex.com
A forward-thinking consulting house and venture builder focused on digital acceleration, innovation, and cultivating talent for the success of tomorrow |
405 | |||
| 15 |
YKSyks.com.tr
Specializing in sectoral informing, our team expands knowledge in facilities and property management, offering reports and services in energy, waste, security, and more |
400 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 16 |
KoçZerkoczer.com
Leader in procurement & supply chain management with 20+ years of experience, providing end-to-end solutions, strategic roadmaps, mass purchases, and technological solutions |
390 | |||
| 17 |
Nagarro + MBISnagarro.com.tr
Leading digital engineering and consulting firm offering innovative solutions for digital transformation, specializing in SAP services for global markets |
369 | |||
| 18 |
Sistem Global Danışmanlık A.Ş.sistemglobal.com.tr
Provider of financial, legal, and consultancy services for technology companies, specializing in corporate finance, tax, audit, patents, and international funds |
368 | |||
| 19 |
E Mali Müşavirlikemusavirlik.com
Specializing in advisory services in Mali, providing expert guidance and consulting solutions to clients |
345 | |||
| 20 |
Forvis Mazars Türkiyeforvismazars.com
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 |
334 | |||
| 21 |
FEV Türkiyefev.com
A provider of turnkey engineering solutions in the automotive industry, specializing in vehicle development, software, autonomous driving, and propulsion systems |
330 | |||
| 22 |
Solvia Digital Solutionssolviads.com
Design, integrate, and optimize SAP and IT solutions to enhance agility, resilience, and long-term digital transformation for businesses. |
318 | |||
| 23 |
RİSUS INTERNATIONALrisusinternational.com
Specializing in change management, analysis, and training services to improve organizational performance through customized solutions and development programs |
244 | |||
| 24 |
VİZYONvizyongrubu.com
Specializing in tax, auditing, and consulting services to provide comprehensive financial guidance and support to clients |
233 | |||
| 25 | 205 | ||||
| 26 |
Carettacaretta.net
A software company offering custom development, IT consultancy, and outsourcing services, specializing in solutions for the pharmaceutical sector, with global quality standards |
186 | |||
| 27 |
GoLive Yazılım A.Şgolive.com.tr
Specializes in SAP ERP implementation and SAP S/4HANA transformation projects, providing expert consultancy, support, and solutions for digital transformation in all industries |
185 | |||
| 28 |
MDP Groupmdpgroup.com
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 |
149 | |||
| 29 |
Experilabs (SahaBT Yazılım)experilabs.com
Providing tailored solutions for corporate clients through consulting, training, outsourcing, test automation, and expertise in software solutions, Java, RPA, Devops, and project management |
117 | |||
| 30 |
VBMvbm.com.tr
Innovative consultancy specializing in Uipath RPA, Test Automation, Document Understanding, offering software development services, UiPath training, and global support |
112 | |||
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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 Istanbul
- The largest companies in Istanbul 1,393
- Multinational companies in Istanbul 348
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- Retail chains in Istanbul 188
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- Corporate groups and holding companies in Istanbul 134
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- IT services companies in Istanbul 50
- Financial Services companies in Istanbul 47