The 2004–05 Primeira Liga was the 71st edition of top flight of Portuguese football.
The league was contested by 18 clubs, and was considered one of the most competitive seasons in recent years.
At the bottom of the table, Moreirense, Estoril and Beira-Mar were relegated to the Liga de Honra.
The Footballer of the Year award was won by the Portuguese Ricardo Quaresma of Porto.
The Portuguese Golden Shoe award was won by the Brazilian Liédson of Sporting CP, scoring 25 goals.