2021 Amex-Istanbul Challenger II

The 2021 Amex-Istanbul Challenger II was a professional tennis tournament played on hard courts. It was the 35th edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Istanbul, Turkey between 13 and 19 September 2021.

Seeds

 * 1 Rankings are as of 30 August 2021.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇹🇷 Sarp Ağabigün
 * 🇷🇴 Victor Vlad Cornea
 * 🇹🇷 Koray Kırcı

The following players received entry from the qualifying draw:
 * 🇺🇸 Nick Chappell
 * 🇧🇪 Christopher Heyman
 * 🇫🇷 Laurent Lokoli
 * 🇧🇦 Aldin Šetkić

The following player received entry as a lucky loser:
 * 🇫🇷 Geoffrey Blancaneaux

Singles

 * 🇦🇺 James Duckworth def. Wu Tung-lin 6–4, 6–2.

Doubles

 * 🇲🇩 Radu Albot / 🇲🇩 Alexander Cozbinov def. Antonio Šančić / 🇳🇿 Artem Sitak 4–6, 7–5, [11–9].