2003–04 Segunda Divisão B

The 2003–04 Segunda Divisão season was the 70th season of the competition and the 54th season of recognised third-tier football in Portugal.

Overview
The league was contested by 59 teams in 3 divisions with SC Espinho, Gondomar SC and SC Olhanense winning the respective divisional competitions and gaining promotion to the Liga de Honra. The overall championship was won by SC Espinho.