The 2003–04 season was the 104th season in Società Sportiva Lazio's history and their 16th consecutive season in the top-flight of Italian football.

Despite financial problems, Lazio attained a respectable 6th place in Serie A and won the Coppa Italia, defeating Juventus in the two-legged final.

Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.

Players may hold more than one non-FIFA nationality.