| Date: | 17–23 April |
| Edition: | 8th |
| Surface: | Clay |
| Location: | Oeiras, Portugal |
| Champs: |  Zsombor Piros |
| Champd: |  Victor Vlad Cornea / Franko Škugor |
| Before Name: | Open de Oeiras III |
| After Year: | 2023 |
| After Name: | Open de Oeiras II |
The 2023 Open de Oeiras was a professional tennis tournament played on clay courts. It was the eighth edition of the tournament which was part of the 2023 ATP Challenger Tour. It took place in Oeiras, Portugal between 17 and 23 April 2023.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 France | Adrian Mannarino | 47 | 1 | |
| France | Alexandre Müller | 96 | 2 | |
 Austria | Sebastian Ofner | 120 | 3 | |
 Argentina | Juan Manuel Cerúndolo | 123 | 4 | |
| João Sousa | 146 | 5 | ||
 Japan | Kaichi Uchida | 160 | 6 | |
| Hungary | Zsombor Piros | 167 | 7 | |
 Italy | Andrea Vavassori | 176 | 8 |
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw as a special exempt:
The following player received entry into the singles main draw as an alternate:
The following players received entry from the qualifying draw:
Cezar Crețu
Billy Harris
Pablo Llamas Ruiz Daniel Mérida
Petr NouzaThe following player received entry as a lucky loser:
See main article: 2023 Open de Oeiras – Singles.
Zsombor Piros def. Juan Manuel Cerúndolo 6–3, 6–4.See main article: 2023 Open de Oeiras – Doubles.
Victor Vlad Cornea / Franko Škugor def. 
Marcelo Demoliner / Andrea Vavassori 7–6(7–2), 7–6(7–4).