The 2023 Istanbul Challenger was a professional tennis tournament played on hard courts. It was the 37th edition of the tournament which was part of the 2023 ATP Challenger Tour. It took place in Istanbul, Turkey between 4 and 10 September 2023.

Country	Player	Rank1	Seed
KOR	Kwon Soon-woo	104	1
NED	Jesper de Jong	141	2
SVK	Lukáš Klein	155	3
CRO	Dino Prižmić	176	4
BEL	Gauthier Onclin	198	5
FRA	Harold Mayot	204	6
BIH	Damir Džumhur	211	7
SVK	Norbert Gombos	217	8

• ¹ Rankings are as of 28 August 2023.^[1]

The following players received wildcards into the singles main draw:

• Tuncay Duran
• Koray Kırcı
• Ergi Kırkın

The following players received entry from the qualifying draw:

• Blaise Bicknell
• Leo Borg
• Daniel Cukierman
• Martin Damm
• Marsel İlhan
• Yshai Oliel

• Damir Džumhur def. Lukáš Klein 7–6^(7–5), 6–3.

• Luke Johnson / Skander Mansouri def. Sander Arends / Aisam-ul-Haq Qureshi 7–6^(7–3), 6–3.