The 1976–77 I liga was the 51st season of the Polish Football Championship and the 43rd season of the I liga, the top Polish professional league for association football clubs, since its establishment in 1927.

The league was operated by the Polish Football Association (PZPN).

The champions were Śląsk Wrocław, who won their 1st Polish title.

The season started on 21 August 1976 and concluded on 25 May 1977 (autumn-spring league).

A total of 16 teams participated, 14 of which competed in the league during the 1975–76 season, while the remaining two were promoted from the 1975–76 II liga.