Senior Management

Ümit Önal, a graduate of Istanbul University Faculty of Communication, started his professional life in media and communication sector. He joined Turkuvaz Media Group in 2007 and served as the General Manager of ATV, Advertising Group President and Executive Board Member, respectively, until 2015. After being appointed as the Board Member and CEO of Digitürk in 2015, he managed Digiturk's sales process to BeIN Media Group. Önal joined Türk Telekom family as the Assistant General Manager responsible for Sales and Customer Services at the end of 2016, and in December 2018, he was appointed as the Assistant General Manager responsible for Marketing and Customer Services, and in August 2019, he was appointed as the CEO of the company. Having more than 20 years of experience in the media and communication sector, Önal has contributed significantly to the process of radical change in the Turkish media, and he continues to lead the digital and technological transformation of Türkiye in Türk Telekom.

Throughout his career, Ümit Önal has actively taken positions in national and international associations. Önal served as the Chairman of the Board of Mobile Telecommunication Operators Association (m-TOD) in 2020; he is still actively Chairman of TV Monitoring and Research Committee (TİAK A.Ş.); Board Member at Advertisers Association (RVD), member to Foreign Investors Association (YASED), Board Member at Yıldız Teknopark of Yıldız Technical University and US Business Council Member of Foreign Economic Relations Board (DEIK); and he represents Türk Telekom at Association of TV Broadcasters (TVYD).

Önal joined the Türk Telekom family as the Assistant General Manager responsible for Sales and Customer Services at the end of 2016, and was appointed as the Assistant General Manager responsible for Marketing and Customer Services in December 2018. In August 2019, Ümit Önal was appointed as the CEO of the company and has been serving as a member of the Türk Telekom Board of Directors since March 2022.

In 2006, he graduated from Middle East Technical University, Faculty of Economics and Administrative Sciences, Department of Economics, and in 2015 he received his Master's degree in Public Administration from Carnegie Mellon University. In 2006, he started working as an assistant expert at the Undersecretariat of Treasury, General Directorate of Foreign Economic Relations.

As of 2009, he worked at the General Directorate of Public Finance as an expert in receivables management, budget monitoring and analysis, and cash management departments, respectively. Between 2017 and 2020, he served as the Head of Department responsible for Credit Risk Management and then Market Risk Management at the same General Directorate. Between 2020-2021, he served as Assistant General Manager responsible for cash and risk management. Between 2021 and 2022, he served as a member of the Board of Directors of the General Directorate of State Supply Office.

Between 2021 and 2025, he served as the General Manager of Public Finance responsible for Treasury operations including cash, debt, risk and receivables management. In 2022, he became a member of the Board of Directors of the Development Bank of Turkey, and since 2023, he has been serving as Vice Chairman of the Board of Directors.

Ömer Karademir is serving as Finance Assistant General Manager of Türk Telekom since March 2025.

Dr. Ali Arıöz was born in Ankara in 1978. He graduated from Non-Commissioned Officer Preparatory School in 1994, and Middle East Technical University, Department of International Relations in 1999. Ali ARIÖZ, who studied banking and finance at Ziraat Bank Banking School between October 1999 and October 2000, received his Master's degree in Public Administration from Carnegie Mellon University in 2009 and his PhD in Finance from Hacettepe University in 2023.

In 2000, he passed the competition exam and started to work as an Assistant Competition Expert at the Competition Authority and was appointed as a Competition Expert in 2004 after defending his thesis titled “Liberalization in the Telecommunications Sector”. With the titles of Assistant Expert, Expert and Chief Expert, he conducted audits, research, investigations, SDIF (Savings Deposit Insurance Fund) asset sales and privatization projects in the telecommunications and media sectors. In 2013, he was appointed as the International Relations Coordinator; in 2015, he was appointed as the Head of the Department of External Relations, Training and Competition Advocacy; and in 2018, he was appointed as the Head of the First Audit and Implementation Department responsible for the energy, petroleum and petrochemicals, chemical products, mining, machinery and equipment sectors. Ali Arıöz, who also served as the acting Press and Public Relations Counsel for a while in the course of these duties, served as a member of various commissions and boards established under the Competition Authority, as well as the Conciliatory Commission of the Ministry of Culture and Tourism and the Evaluation Board of TÜBİTAK SOBAG Call Program.

Since 2024, Ali Arıöz has been teaching “Public Regulation in Industries” course in Turkish and English at Başkent University, Department of Economics and has published articles and book chapters on his fields of study.

He speaks English fluent and French intermediate.

Dr. Ali Arıöz, is serving as Support Services and Procurement Management Assistant General Manager of Türk Telekom since March 2025.

Upon completing his undergraduate education at McGill University with a double major in International Relations and Economics, İskender Bayrak had his master's degree in Human Resources Management at the same university.

He started his career at THY (Turkish Airlines) Canada in 2003, then worked as a project manager at Deva Logistics in North America, and carried out global projects across different sectors within the UK-based human resources consultancy firm The Miles Partnership.

Having joined Türk Telekom in 2011 as the HR business partner responsible for commercial functions, Bayrak served as the HR business partner responsible for channel integration and the corporate business unit during the integration process of the group companies.

İskender Bayrak was appointed as the HR Business Partnership Director in 2018 and since then he has been responsible for the recruitment, compensation management, employee experience, and outsourcing management functions. His most recent title is Employee Experience and Compensation Management Director.

Bayrak, who participated in the INSEAD Strategic Leadership program, has the professional coaching certificate of the Coaching Training Institute (CTI). He speaks advanced English and French.

İskender Bayrak is serving as Human Resources Assistant General Manager of Türk Telekom since March 2025.

Starting his career as an auditor at the Ministry of Agriculture and Rural Affairs in 1997, he served as Deputy Private Secretary and Minister Advisor between 2003 and 2005. During this period, he actively took part in various commissions within the scope of the restructuring of the Ministry, and the development of the financial infrastructure, accounting systems and legislation activities of agricultural non-governmental organizations.

In 2005, he was appointed as Internal Auditor to the Scientific and Technological Research Council of Turkey (TÜBİTAK). Later that year, he was appointed as the Head of Internal Audit and held this position until 2014. During his presidency, he provided consultancy services to improve corporate business processes, as well as the development of internal control and internal audit systems. He also gave trainings and seminars and wrote articles within the scope of promoting and developing internal audit activity.

In 2014, he was appointed as the Chairman of the Board of Inspectors of TÜRKSAT Satellite Communication, Cable TV and Management A.Ş. and served in this position until January 2024. In TÜRKSAT; he led the process of establishing and developing an audit system in line with the Global Internal Audit Standards. In addition to his duty as Chairman, he actively participated in important activities in the process of updating the company's legislation at all levels, creating new regulations and institutionalization, and served as a Commission Member and Commission Chairman. He served as a consultant to the General Manager, the Audit Committee and the Board of Directors on administrative, financial and fiscal issues and process improvement.

In January 2024, Mr. Çavuşoğlu was appointed as the Head of Internal Audit at Türk Telekomünikasyon A.Ş. He has been a member of the Institute of Internal Auditing-Turkey (TİDE) since 2014 and a member of the Audit Board of the Access Providers Association (ESB) since 2016. He acted as a founding member of the Board of Directors of TCDD Teknik A.Ş. in 2018-2019. He served as the Vice Chairman of the Board of Directors of the Public Internal Auditors Association (KIDDER) in 2022&2023, and currently holds a position as a member of the Advisory Board of KİDDER.

He completed his undergraduate education at Istanbul University, Faculty of Political Sciences, Department of Public Administration and his master's degree at Selçuk University, Faculty of Economics and Administrative Sciences, Department of Public Administration.

He graduated from Istanbul University, Faculty of Political Sciences, Department of Public Finance in 2001. Before starting his corporate career as an Accounting Specialist at TTNET Corp. in 2008, he had worked in the accounting and financial consultancy area in various companies.

He took part in many projects in the process of structuring corporate functions at TTNET Corp, and upon taking over various managerial positions in the Finance department, he served as the Director of Sales Finance and Fraud Control and as CEO Office Director respectively until the integration of Türk Telekom Group.

After the integration, he managed different departments under the Sales function, and then served as
the Channel Operations Director and Sales Development Director under Türk Telekom Consumer Sales
Department.

Osman Çolak, who most recently served as TT CEO Office Director, has been serving as Consumer Sales Assistant General Manager since November 2023.

Mustafa Eser graduated from the Department of Physics of Hacettepe University in 1996. Between 1996 and 1998, he conducted his master’s degree studies at the University of Cologne and Heinrich Heine University in Düsseldorf. Since 1998, he has been taking part in Information and Education sectors as an entrepreneur and a manager. Between 2007 and 2014, he worked at Türksat A.Ş as Director. Between 2014 and 2017, he worked as the Manager responsible from Public Sector Relations and Regulation at Digitürk. Since May 2017, he served as the Public Sales Director at Türk Telekom. Mustafa Eser, is the Chairman of the Board of Directors of Sebit A.Ş., a subsidiary of Türk Telekom and Türkiye’s leading educational technology company, also serves as a member of the Board of Directors of Türk Telekom Sports Club and is responsible for the basketball branch.

Mustafa Eser is serving as Corporate Sales Assistant General Manager of Türk Telekom since April 2020.

Gökhan Evren was born in Tokat in 1978. After graduating from Trabzon Yomra Science High School, he graduated from Marmara University, Department of Computer Engineering in 2000. He received a Master's degree (MS) in Science and Technology Policy from Middle East Technical University (METU) and also a Master's degree (MA) in Communications from the University of Westminster in London. He completed the Cyber Security Program at Carnegie Mellon University and the Regulation Program at Michigan State University in USA. He continues his PhD studies in Political Science at Hacettepe University.

After working as a software engineer in private sector from 2000, Gökhan Evren joined the Information and Communication Technologies Authority in October 2001, and worked as an ICT expert and chief expert in tariffs, competition, consumer rights, information technologies, etc. departments; after 2014, he has managed regulation, audit and cyber security operations with a title of manager, head of department and Deputy Head of the Institution respectively.

He worked for the establishment of the National Cyber Incident Response Center (USOM) within ICTA, creation of malware and digital analysis laboratories, development of domestic and national cyber security solutions and systems, acquisition of cyber threat intelligence capabilities, creation of cyber security organisational structure throughout the country and capacity building processes.

He had been serving as the General Manager of Communications at the Ministry of Transport and Infrastructure since 2018 and implemented projects for the expansion of universal service mobile infrastructure and networks. He is also vice chairman of the Cyber Security Working Group at the International Telecommunications Union (ITU). He is married and has one child.

Gökhan Evren, most recently served as Wholesale Services Assistant General Manager. Gökhan Evren, is serving as Information Technologies Assistant General Manager of Türk Telekom since March 2025.

After graduating from Istanbul Kültür University, Department of Industrial Engineering, Ahmet Kamil Gençel completed his MBA at the same university. He started his career in the Regulatory Strategy department at Avea. He took an active role in critical processes such as mobile number portability and 3G tender process. During the Liberalization of our country's Telecommunications sector, when the number of operators in the market increased rapidly, he took over a strategic role in the sector by serving as Inter-Operator Relations and Wholesale Services Manager.

Following this position, Ahmet Kamil Gençel served as Strategy & PMO Director at Turkish Radio and Television Corporation TRT, where he managed the preparation process of TRT's new term strategy and business plans, the Corporate Transformation process, the establishment of TRT World, and he took an active role on the formation of TRT's digital VOD platform and game vertical. Before joining our company, he served as the Assistant General Manager responsible for TRT Strategy & Digital Products.

Ahmet Kamil Gençel, most recently served as Head of Strategy, Investment and Subsidiary Management. Ahmet Kamil Gençel, is serving as Strategy and Wholesale Services Assistant General Manager of Türk Telekom since March 2025.

Serdar Toraman graduated from Istanbul University, Department of Electronic Engineering in 1999. Toraman, who started his career at IBM, worked in various positions at Sentim Bilişim Teknolojileri, ServisNET Telekomünikasyon Hizmetleri under NETAŞ, and Eczacıbaşı Bilişim.

Toraman, who has undertaken important roles in leading companies in the field of information technologies, worked in executive positions at Avnet Technology (TechData), Borsa Istanbul and Information Technologies and Communications Authority.

Afterwards, Toraman served as IT Director and Consultant at Türk Telekom subsidiary AssisTT Guidance and Customer Services company, and served as the General Manager of PTT Bilgi Teknolojileri A.Ş.

Serdar Toraman served as the CEO of our subsidiary company İnnova between 2020-2025.

Serdar Toraman is serving as Head of Corporate Risk of Türk Telekom since March 2025.

Tahsin Kaplan who has more than 20 years of experience in the field of Corporate Law and Regulation in both private and public institutions, graduated from Marmara University Faculty of Law in 1999.After starting his professional career as a freelance lawyer, he took office under the titles of Legal Adviser, Group Head of Legal Affairs and held several Board Memberships in finance and media sectors. He has been working as a freelance lawyer since 2016.

Tahsin Kaplan is serving as Legal and Regulation Assistant General Manager of Türk Telekom since August 2021.

He was born in Elazığ in 1973. After graduating from the Department of Electronics of Elazığ Central Technical High School, he completed his undergraduate education at Fırat University, Department of Mechanical Engineering. He has a master's degree with thesis in Business Management from Bahçeşehir University. He started his career in 1993 as Elazığ PTT Network Group Chief Engineer, and in 2000, he worked at Marketing Department of Türk Telekom Elazığ Provincial Directorate. In 2003, he was appointed as the Organization and Process Management Manager of the Strategy Directorate of Türk Telekom General Directorate, and then served as the Organizational Development Manager. Between 2011 and 2016, he worked as Deputy Regional Director of Access and Deputy Regional Manager of Commercial Activities at Türk Telekom Ankara Regional Directorate of Central Anatolia. Between 2016 and 2020, he managed the institutional transformation program of the CBRT as Assistant General Manager at the Central Bank of the Republic of Turkey and later as General Manager of Corporate Transformation.  In 2020, he first served as Assistant General Manager of Business Development and then as General Manager at Ulak İletişim A.Ş., a telecommunications company affiliated to the Defense Industry Presidency. In February 2024, he left his position as General Manager of Ulak İletişim A.Ş. and has become the General Manager and Group CEO of Molekül A.Ş., which includes Masttech, Inttow and Numesys companies. He is married and has two children.

Zeynep Özden, graduated from Bilgi University's Department of Public Relations in English, started her career in Corporate Customer Services at BP Petroleum, and took on professional and managerial responsibilities in the fields of strategic planning and performance management in the communication and media sectors. She joined Türk Telekom Group as 'Commercial Planning Director' in 2017 and carried out the Projects for Efficiency of Sales Channels and Restructuring of Corporate Sales Customer Segmentation. Özden, most recently served as the 'Marketing Intelligence and Customer Experience Director', responsible for Marketing Planning, Pricing, Customer Experience and Customer Analytics. Zeynep Özden is serving as Marketing and Customer Experience Assistant General Manager since September 2022.