The 2023 Nonthaburi Challenger II was a professional tennis tournament played on hard courts. It was the 5th edition of the tournament which was part of the 2023 ATP Challenger Tour. It took place in Nonthaburi, Thailand from 9 to 14 January 2023.
Singles main-draw entrants
Seeds
1 Rankings are as of 2 January 2023.
Other entrants
The following players received wildcards into the singles main draw: Palaphoom Kovapitukted Kasidit Samrej Wishaya Trongcharoenchaikul
The following players received entry into the singles main draw as alternates: Prajnesh Gunneswaran Billy Harris
The following players received entry from the qualifying draw: Alafia Ayeni Arthur Cazaux Evgeny Donskoy Giovanni Fonio Jason Jung Henri Squire
Champions
Singles
Arthur Cazaux def. Lloyd Harris 7–6(7–5), 6–2.
Doubles
Yuki Bhambri / Saketh Myneni def. Christopher Rungkat / Akira Santillan 2–6, 7–6(9–7), [14–12].