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, where he served respectively as General Manager of ATV, President of the Advertising Group, and Executive Board Member until 2015. After being appointed the Board Member and CEO of Digitürk in 2015, he oversaw Digitürk’s sale to BeIN Media Group. Önal joined the 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 the Assistant General Manager responsible for Marketing and Customer Services, and in August 2019, he was appointed the CEO of the company. With more than 20 years of experience in the media and communication sector, Önal has played a significant role in the transformation of Turkish media and continues to lead Türkiye’s digital and technological advancement through Türk Telekom.

Throughout his career, Ümit Önal has held active roles in both national and international associations. Önal served as the Chairman of the Board of Mobile Telecommunication Operators Association (m-TOD) in 2020 and 2022; he is also an active member to Foreign Investors Association (YASED), Board Member at US Business Council Member of Foreign Economic Relations Board (DEIK).

In August 2019, Ümit Önal was appointed the CEO of the company and has served as a member of the Türk Telekom Board of Directors since March 2022.

In 2006, Ömer Karademir 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 began his career as an Assistant Expert at the Undersecretariat of Treasury, General Directorate of Foreign Economic Relations.

From 2009 onwards, 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 Türkiye, and between 2023 and 2025, he served as Vice Chairman of the Board of Directors.

Ömer Karademir has served 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 Arıöz, 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 entrance examination and began working as an Assistant Competition Expert at the Competition Authority and was appointed as a Competition Expert in 2004 after defending his thesis titled “Liberalisation in the Telecommunications Sector.” In his roles as Assistant Expert, Expert and Chief Expert, he conducted audits, research, investigations, SDIF (Savings Deposit Insurance Fund) asset sales and privatisation projects in the telecommunications and media sectors. In 2013, he was appointed as the International Relations Coordinator; in 2015, Head of the Department of External Relations, Training and Competition Advocacy; and in 2018, Head of the First Audit and Implementation Department responsible for the energy, petroleum and petrochemicals, chemical products, mining, machinery and equipment sectors. Ali Arıöz also served as Acting Press and Public Relations Counsel during this time. He has been 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 the TÜBİTAK SOBAG Call Programme.

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

He is fluent in English and has intermediate proficiency in French.

Dr. Ali Arıöz, has served 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 obtained his Master’s degree in Human Resources Management at the same university.

He started his career at THY (Turkish Airlines) Canada in 2003, later working 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.

After joining Türk Telekom in 2011 as the HR Business Partner responsible for commercial functions, Bayrak also oversaw 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 has since been responsible for recruitment, compensation management, employee experience, and outsourcing management functions. His most recent position was Employee Experience and Compensation Management Director.

Bayrak has completed the INSEAD Strategic Leadership Programme and holds a professional coaching certificate from the Coaching Training Institute (CTI). He is fluent in English and French.

İskender Bayrak has served as Human Resources Assistant General Manager of Türk Telekom since March 2025.

Mustafa Çavuşoğlu 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 began his career as an auditor at the Ministry of Agriculture and Rural Affairs in 1997 and served as Deputy Private Secretary and Minister Advisor between 2003 and 2005. During this period, he actively participated in various commissions focused on the restructuring of the Ministry, and the development of financial infrastructure, accounting systems, and legislative activities for agricultural non-governmental organisations.

In 2005, he was appointed as Internal Auditor to the Scientific and Technological Research Council of Türkiye (TÜBİTAK). Later that year, he was appointed as the Head of Internal Audit and held this position until 2014. During his tenure, he provided consultancy services aimed at improving corporate business processes, as well as developing internal control and internal audit systems. He also delivered training sessions and seminars and wrote articles to promote and advance internal auditing practices.

In 2014, he was appointed as the Chairman of the Board of Inspectors at TÜRKSAT Satellite Communication, Cable TV and Management A.Ş., a role he held until January 2024. At TÜRKSAT, he led the establishment and development of an audit system aligned with the Global Internal Audit Standards. In addition to his role as Chairman, he actively contributed to updating the company’s legislation at all levels, drafting new regulations, and supporting institutionalisation, serving as both Commission Member and Chairman. He served as a consultant to the General Manager, the Audit Committee and the Board of Directors on administrative, financial and fiscal matters as well as process improvement.

In January 2024, Mr. Çavuşoğlu was appointed the Head of Internal Audit at Türk Telekomünikasyon A.Ş. He has been a member of the Institute of Internal Auditing- Türkiye (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.

Mustafa Çavuşoğlu has served as the Head of Internal Audit at Türk Telekom since January 2024.

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 A.Ş. in 2008, he had worked accounting and financial consultancy roles at various companies.

He was involved in numerous projects related to the structuring of corporate functions at TTNET A.Ş. After assuming various managerial positions in the Finance Department, he served as Director of Sales Finance and Fraud Control, and subsequently as CEO Office Director, until the integration of the Türk Telekom Group.

Following the integration, he managed various departments within the Sales function, and went on to serve as Channel Operations Director and Sales Development Director under the Türk Telekom Consumer Sales Department.

Osman Çolak, who most recently served as TT CEO Office Director, has served 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 pursued his Master’s degree studies at the University of Cologne and Heinrich Heine University in Düsseldorf. Information and Education sectors as an entrepreneur and a manager. Since 1998, he has been active in the information and education sectors as both 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. He also serves as a member of the Board of Directors of Türk Telekom Sports Club, where he is responsible for the basketball branch.

Mustafa Eser has served 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 holds a Master’s degree (MS) in Science and Technology Policy from Middle East Technical University (METU) and a Master’s degree (MA) in Communications from the University of Westminster in London. He completed the Cybersecurity Program at Carnegie Mellon University and the Regulation Program at Michigan State University in the USA. He is currently pursuing a PhD 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. He served as ICT Expert and Chief Expert across departments including tariffs, competition, consumer rights, and information technologies. Since 2014, he has held managerial roles, serving as Manager, Head of Department, and Deputy Head of the Institution, overseeing regulation, auditing, and cybersecurity operations.

He contributed to the establishment of the National Cyber Incident Response Centre (USOM) within ICTA, the creation of malware and digital analysis laboratories, the development of domestic and national cybersecurity solutions and systems, the acquisition of cyber threat intelligence capabilities, and the formation of the national cybersecurity organisational structure and capacity-building processes.

He has served as General Manager of Communications at the Ministry of Transport and Infrastructure from 2018, where he has led projects to expand universal service mobile infrastructure and networks. He also serves as Vice Chairman of the Cybersecurity Working Group at the International Telecommunication 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 played an active role in key processes such as mobile number portability and the 3G tender process. During the liberalisation of our country’s Telecommunications sector, when the number of operators in the market increased rapidly, he assumed a strategic role 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 of TRT’s new term strategy and business plans, the Corporate Transformation process, the establishment of TRT World, and played an active role on the formation of TRT’s digital VOD platform and game vertical. Prior to 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.

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 held various positions, including legal adviser and group head of legal affairs, and he served as a board member in the finance and media sectors. He has been working as a freelance lawyer since 2016.

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

Zafer Orhan 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 a 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 the Marketing Department of Türk Telekom Elazığ Provincial Directorate. In 2003, he was appointed Organisation and Process Management Manager of the Strategy Directorate of Türk Telekom General Directorate and later served as the Organisational Development Manager. Between 2011 and 2016, he worked as Deputy Regional Director of Access and Deputy Regional Manager of Commercial Activities at the 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 Türkiye 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 with the Presidency of Defence Industry. In February 2024, he stepped down as General Manager of Ulak İletişim A.Ş. and became the General Manager and Group CEO of Molekül A.Ş., which includes Masttech, Inttow and Numesys companies.

Zafer Orhan has served as Assistant General Manager of Network at Türk Telekom since July 2024.

Zeynep Özden graduated from the Department of Public Relations (English) at Bilgi University. She began her professional career in Corporate Customer Services at BP and later held both professional and managerial roles in the communications and media sector, focusing on strategic planning and performance management. In 2017, she joined Türk Telekom Group as Commercial Planning Director, where she led key initiatives such as “Efficiency of Sales Channel” and the “Restructuring of Corporate Sales Customer Segmentation.” Zeynep Özden later served as the Marketing Intelligence and Customer Experience Director, overseeing marketing, customer services planning, pricing, customer experience, and customer analytics.

Since September 2022, Zeynep Özden has served as Marketing and Customer Experience Assistant General Manager.

Serdar Toraman graduated from Istanbul University, Department of Electronic Engineering in 1999. Toraman began his career at IBM and held various positions at Sentim Bilişim Teknolojileri, ServisNET Telekomünikasyon Hizmetleri (a NETAŞ company), and Eczacıbaşı Bilişim.

Toraman has held senior roles in leading information technology companies, serving in executive positions at Avnet Technology (TechData), Borsa Istanbul, and the Information and Communication Technologies Authority.

Toraman later served as IT Director and Consultant at AssisTT Guidance and Customer Services, a subsidiary of Türk Telekom, and as General Manager of PTT Bilgi Teknolojileri A.Ş. Serdar Toraman served as the CEO of our subsidiary company İnnova between 2020-2025.

Serdar Toraman has served as Head of Corporate Risk of Türk Telekom since March 2025.