2024 Open de Oeiras

Country	Player	Rank1	Seed
ITA	Fabio Fognini	94	1
BRA	Thiago Monteiro	113	2
HUN	Zsombor Piros	114	3
ARG	Francisco Comesaña	116	4
USA	Emilio Nava	125	5
FRA	Térence Atmane	133	6
USA	Nicolas Moreno de Alboran	134	7
ARG	Juan Manuel Cerúndolo	152	8
NED	Jesper de Jong	155	9

• ¹ Rankings are as of 8 April 2024.^[2]

The following players received wildcards into the singles main draw:

• Gastão Elias
• Jaime Faria
• Frederico Ferreira Silva

The following players received entry into the singles main draw as special exempts:

• Jozef Kovalík
• Stefano Napolitano

The following players received entry from the qualifying draw:

• Adrian Andreev
• Mathys Erhard
• Gauthier Onclin
• Valentin Royer
• Tseng Chun-hsin
• Samuel Vincent Ruggeri

The following player received entry as a lucky loser:

• Maks Kaśnikowski

• Francisco Comesaña def. Ugo Blanchet 6–4, 3–6, 7–5.

• Filip Bergevi / Mick Veldheer def. Sergio Martos Gornés / Petros Tsitsipas 6–1, 6–4.