Province·Marmara Region·Code 41
TÜİK · ADNKS 2025The most common surnames in Kocaeli
As in Türkiye as a whole, the most common surname in Kocaeli is Yılmaz: 33,865 people in 2025. Kaya is second with 22,694. Yılmaz has led Kocaeli every year since 2018.1
- First place
- Yılmaz
- Surnames listed
- 301
The 30 most common surnames in Kocaeli, 2025
| Rank | Surname | People | Per 1,000 | National rank |
|---|---|---|---|---|
| 01 | Yılmaz | 33,865 | 15.7 | 1 |
| 02 | Kaya | 22,694 | 10.5 | 2 |
| 03 | Demir | 21,235 | 9.8 | 3 |
| 04 | Aydın | 20,777 | 9.6 | 9 |
| 05 | Yıldız | 20,099 | 9.3 | 5 |
| 06 | Şahin | 19,058 | 8.8 | 6 |
| 07 | Öztürk | 18,886 | 8.7 | 8 |
| 08 | Çelik | 18,328 | 8.5 | 4 |
| 09 | Yıldırım | 17,580 | 8.1 | 7 |
| 10 | Kılıç | 14,410 | 6.7 | 13 |
| 11 | Özdemir | 12,874 | 6.0 | 10 |
| 12 | Arslan | 11,858 | 5.5 | 11 |
| 13 | Doğan | 10,062 | 4.7 | 12 |
| 14 | Koç | 8,618 | 4.0 | 18 |
| 15 | Aslan | 8,342 | 3.9 | 14 |
| 16 | Kurt | 7,888 | 3.6 | 17 |
| 17 | Kara | 7,817 | 3.6 | 16 |
| 18 | Çetin | 7,761 | 3.6 | 15 |
| 19 | Çakır | 7,744 | 3.6 | 24 |
| 20 | Aktaş | 7,566 | 3.5 | 30 |
| 21 | Turan | 7,472 | 3.5 | – |
| 22 | Yavuz | 7,146 | 3.3 | 23 |
| 23 | Özcan | 7,120 | 3.3 | 25 |
| 24 | Keskin | 6,733 | 3.1 | – |
| 25 | Polat | 6,496 | 3.0 | 19 |
| 26 | Acar | 6,277 | 2.9 | 28 |
| 27 | Korkmaz | 6,272 | 2.9 | 21 |
| 28 | Erdoğan | 6,066 | 2.8 | 26 |
| 29 | Özkan | 6,045 | 2.8 | 22 |
| 30 | Şen | 5,994 | 2.8 | – |
How do these counts compare with Kocaeli’s population?
With an ADNKS population of 2,161,171 in 2025, about 15.7 in every 1,000 people in Kocaeli are called Yılmaz. The 30 listed surnames together cover 363,083 people, 16.8% of the population.1,2
Kocaeli lies in the Marmara Region. According to ADNKS its population grew by 13.4% between 2018 and 2025.2
| 2018 | 1,906,391 |
|---|---|
| 2019 | 1,953,035 |
| 2020 | 1,997,258 |
| 2021 | 2,033,441 |
| 2022 | 2,079,072 |
| 2023 | 2,102,907 |
| 2024 | 2,130,006 |
| 2025 | 2,161,171 |
Which surname leads in the neighbouring provinces?
- BursaBursa: also Yılmaz, with 46,316 people in 2025, 1.4 times as many as in Kocaeli.
- IstanbulIstanbul: also Yılmaz, with 230,115 people in 2025, 6.8 times as many as in Kocaeli.
- SakaryaSakarya: also Yılmaz, with 17,597 people in 2025, 52% of the figure in Kocaeli.
- YalovaYalova: also Yılmaz, with 4,275 people in 2025, 13% of the figure in Kocaeli.
Neighbours: land borders derived from Natural Earth boundaries.3
Has Kocaeli’s top three changed over the years?
| Year | 1. | 2. | 3. |
|---|---|---|---|
| 2018 | Yılmaz 30,542 | Kaya 19,525 | Demir 18,389 |
| 2019 | Yılmaz 31,165 | Kaya 19,954 | Aydın 18,889 |
| 2020 | Yılmaz 31,882 | Kaya 20,571 | Aydın 19,388 |
| 2021 | Yılmaz 32,405 | Kaya 20,928 | Aydın 19,690 |
| 2022 | Yılmaz 33,087 | Kaya 21,568 | Demir 20,126 |
| 2023 | Yılmaz 33,255 | Kaya 21,785 | Demir 20,415 |
| 2024 | Yılmaz 33,579 | Kaya 22,188 | Demir 20,866 |
| 2025 | Yılmaz 33,865 | Kaya 22,694 | Demir 21,235 |
Sources
- 1Türkiye İstatistik Kurumu (TÜİK) · ADNKS, TÜİK Nüfus İsim Portalı: En çok kullanılan soyisimler (ADNKS)
- 2Türkiye İstatistik Kurumu (TÜİK) · ADNKS, TÜİK ADNKS: Cinsiyete göre nüfus, Türkiye ve 81 il
- 3Natural Earth, Natural Earth: Admin-1 boundaries