This selection of professional services firms in Turkey includes large companies specializing in law, accounting, engineering, and IT consulting. Among them are Avukat, a legal practice with 4336 employees, and Serbest Muhasebeci Mali Müşavirlik Hizmetleri, an accounting firm with 3332 employees. Other notable firms include KUCUKYiLMAZ Consulting Co. in motor vehicle manufacturing consulting, and STM, which provides high-technology project management and engineering for defense systems.
The data shows a concentration of headquarters in Istanbul, with many firms established in the early 1980s, such as KPMG Türkiye (founded 1982) and PwC Türkiye (founded 1981). There is also a significant presence of government-affiliated entities like Türk Standardları Enstitüsü, focused on national standards, and TCDD Teknik Mühendislik ve Müşavirlik A.Ş., specializing in railroad engineering.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 | 4,336 | ||||
| 2 |
Serbest Muhasebeci Mali Müşavirlik Hizmetlerismmmemrahkucukdeniz.com
An accounting office in Istanbul providing practical solutions to tax issues for clients nationwide, focusing on communication, trust, and quality service |
3,332 | |||
| 3 |
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 | |||
| 4 |
SMMM SAIT OZDEMIRsaitozdemir.com
Offering tax consultancy, bookkeeping according to business standards, handling SGK procedures, providing financial advisory, establishing accounting systems, assisting with personal and company setup procedures |
2,137 | |||
| 5 |
Türk Standardları Enstitüsütse.org.tr
Development and enforcement of national standards for products, services, and procedures under government oversight and legal framework. |
1,560 | |||
| 6 |
STMstm.com.tr
Provides high technology project management, engineering, and consultancy services for military systems, developing domestic software and platforms for defense industry procurement operations. |
1,537 | |||
| 7 |
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 | |||
| 8 |
Ünsped Gümrük Müşavirliği ve Lojistik Hizmetler A.Ş.ugm.com.tr
Specializing in international trade logistics and customs services, the company provides quality solutions with a focus on innovation and customer satisfaction |
1,412 | |||
| 9 |
TCDD Teknik Mühendislik ve Müşavirlik A.Ş.tcddteknik.com.tr
A government-owned engineering firm specializing in engineering, consultancy, technology, signaling, energy, certification, and measurement services in various fields |
1,361 | |||
| 10 |
Yüksel Projeyukselproje.com.tr
A leading provider of design, engineering, and consultancy services for various sectors worldwide, with a focus on sustainable and innovative projects |
1,284 | |||
| 11 |
PwC Türkiyepwc.com.tr
A global network providing quality assurance, advisory, and tax services with a focus on building trust and solving important issues |
1,277 | |||
| 12 |
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 | |||
| 13 |
Deloitte Turkeydeloitte.com.tr
The company provides audit, consulting, financial advisory, risk management, tax services to public and private clients across various industries globally |
978 | |||
| 14 |
Solmazsolmaz.com
A leading logistics service provider offering customs consultancy, international transportation, supply chain management, express courier, and insurance services with over 1,200 expert staff nationwide |
891 | |||
| 15 | 870 | ||||
| 16 |
Serbest Muhasebeci Mali Müşavir
Beauty institute offering a variety of treatments such as hammam, massages, manicures, pedicures, hair styling, facials, and women's waxing services |
711 | |||
| 17 |
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 | |||
| 18 |
EMAY INTERNATIONAL ENGINEERING and CONSULTANCY Inc.emay.com
A leading engineering and consultancy firm in Turkey, offering services in transportation, buildings, and water & environment sectors with a focus on architectural and engineering projects |
704 | |||
| 19 |
Data Gümrük Müşavirliğidatagumrukleme.com
A logistics business that has expanded its services and branches, focusing on customer satisfaction with modern management techniques and technological infrastructure |
703 | |||
| 20 | 702 | ||||
| 21 |
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 | |||
| 22 |
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 | |||
| 23 | 
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 | |||
| 24 |
mediSMART Contract Research Organizationmedismart.com.tr
Clinical Research Organization in Turkey, offering efficient solutions for drug development with a team of over 350 employees |
472 | |||
| 25 |
TÜMAŞ TÜRK MÜHENDİSLİK, MÜŞAVİRLİK VE MÜTEAHHİTLİK A.Ş.tumas.com.tr
Providing pre-project planning, design, engineering, consultancy, and construction services for all project stages, including tendering, supervision, and post-implementation services |
471 | |||
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. | |||||
| 26 | 426 | ||||
| 27 |
OKUL YAPIokulyapi.com
Innovative and effective educational spaces designed by OKULYAPI for future generations, providing turnkey projects and various classroom concepts in Turkey |
422 | |||
| 28 |
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 | |||
| 29 |
DefineXteamdefinex.com
A forward-thinking consulting house and venture builder focused on digital acceleration, innovation, and cultivating talent for the success of tomorrow |
405 | |||
| 30 |
NKY Architects and Engineersnky.com.tr
Specialized in project management and design for hospitals and educational facilities, providing professional services worldwide with a focus on quality development |
405 | |||
| 31 |
SIGMAsigmamuhendislik.com.tr
With over 30 years of experience, we are a trusted partner in engineering and consulting services for leading organizations in Turkey |
394 | |||
| 32 |
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 | |||
| 33 |
Mayen Telekomünikasyon Hizmetleri A.Ş.mayen.com
Mayen offers innovative outsourcing solutions in various sectors, including customer services, RPA, digital training, social media monitoring, HR, payroll, and testing services |
380 | |||
| 34 |
UBM ULUSLARARASI BIRLESMIS MUSAVIRLER MUSAVIRLIK HIZMETLERI A.Şubm.com.tr
A leading technical consultancy specializing in environmental, infrastructure, and transportation projects, with expertise in financial analysis and project management |
377 | |||
| 35 |
Prokon Mühendislik ve Müşavirlik A.Ş.prokon.com.tr
Specializing in design, engineering, and consultancy services for a wide range of industrial projects worldwide with a focus on quality and innovation |
370 | |||
| 36 |
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 | |||
| 37 |
Kendi Agencykendi.agency
An independent advertising agency that values authenticity, creating a space where employees and clients can express their true selves |
366 | |||
| 38 |
Subaşı Gümrük Müşavirliği A.Ş.subasi.net
Established in 1948 as a Customs Brokering entity, employing a skilled team of 470 individuals including 27 customs advisors Specializing in customs clearance services and ensuring accurate, efficient processing through detailed analysis of goods and compliance with relevant regulations |
364 | |||
| 39 |
Autobanautoban.com
Internationally renowned studio specializing in architecture, interiors, product design, and experiential design with a focus on storytelling, craftsmanship, and sensory experiences |
360 | |||
| 40 |
SUR MALİ MÜŞAVİRLİK
Providing accounting and financial consultancy services for individuals and businesses, including bookkeeping, financial statements, tax filings, and advisory services |
355 | |||
| 41 |
MEDEX SMOmedex-smo.com
Specializing in managing clinical research sites, providing site management services to improve trial enrollment, compliance, and performance for pharmaceutical and biotechnology companies |
349 | |||
| 42 |
E Mali Müşavirlikemusavirlik.com
Specializing in advisory services in Mali, providing expert guidance and consulting solutions to clients |
345 | |||
| 43 |
Peoplepeoplecomms.com.tr
A leading media agency in Turkey with a highly skilled team offering integrated communication plans including media planning, buying, strategies, research, and modeling |
341 | |||
| 44 |
Grant Thornton Türkiyegrantthornton.com.tr
An international organization with about 250 professionals in Istanbul, Ankara, and Bursa, providing independent audit, tax, accounting, and advisory services since 1986 |
336 | |||
| 45 |
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 | |||
| 46 |
FEV Türkiyefev.com
A provider of turnkey engineering solutions in the automotive industry, specializing in vehicle development, software, autonomous driving, and propulsion systems |
330 | |||
| 47 |
Solvia Digital Solutionssolviads.com
Design, integrate, and optimize SAP and IT solutions to enhance agility, resilience, and long-term digital transformation for businesses. |
318 | |||
| 48 |
Uniarch Klinik Mühendislik ve Klinik Alan Tasarım A.Şuniarch.com.tr
Uniarch aims to provide secure and efficient healthcare services by offering consultancy, planning, and project services for the design, technology selection, and operations of healthcare facilities |
317 | |||
| 49 |
SPA MÜHENDİSLİKspalinetr.com
Specializing in terminal operation systems in the fuel and chemical industry, designing fire systems, and providing risk analysis solutions for process safety |
316 | |||
| 50 |
DETAM Sirketler Grubudetam.com.tr
A leading consultancy group in Turkey providing a wide range of services in occupational health, safety, environmental services, legal consulting, and HR |
284 | |||
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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.
More company lists in Turkey
- The largest companies in Turkey 3,556
- Multinational companies in Turkey 790
- Manufacturers in Turkey 762
- Companies with in-house R&D in Turkey 512
- Retail chains in Turkey 376
- Companies with a mobile app in Turkey 312
- Corporate groups and holding companies in Turkey 304
- Critical infrastructure operators in Turkey 282
- Public sector organisations in Turkey 227
- Hardware manufacturers in Turkey 224
- Energy companies in Turkey 197
- Food and beverage companies in Turkey 197
- Consumer goods companies in Turkey 193
- Food and Beverage Manufacturing companies in Turkey 184
- Hotel and hospitality groups in Turkey 176
- E-commerce companies in Turkey 172
- Higher Education companies in Turkey 158
- Food and Beverage Services companies in Turkey 149
- Family-owned companies in Turkey 137
- Financial services firms in Turkey 134
- Motor Vehicle Manufacturing companies in Turkey 134
- Publicly traded companies in Turkey 131
- Construction companies in Turkey 129
- Automotive manufacturers and suppliers in Turkey 128