The 1956–57 Rugby Football League season was the 62nd season of rugby league football.
Oldham finished the regular season as the league leaders and then won their fourth Rugby Football League Championship when they beat Hull F.C. 15-14 in the play-off final.
The Challenge Cup winners were Leeds who beat Barrow 9-7 in the final.
Oldham won the Lancashire League, and Leeds won the Yorkshire League. Oldham beat St.Helens 10–3 to win the Lancashire County Cup, and Wakefield Trinity beat Hunslet 23–5 to win the Yorkshire County Cup.
Leeds beat Barrow 9-7 in the Challenge Cup Final played at Wembley Stadium before a crowd of 76,318.
This was Leeds’ eighth Challenge Cup Final win in ten Final appearances. Jeff Stevenson, their scrum half back, was awarded the Lance Todd Trophy for his man-of-the-match performance.