1969–70 Northern Rugby Football League season

The 1969–70 Northern Rugby Football League season was the 75th season of rugby league football in Britain.

Rule change

 * Tactical substitutions were now allowed to occur after half time during a game, they had been permitted before half time since 1964.

Season summary
Leeds had ended the regular season as league leaders for the fourth successive season. St. Helens won their fifth Rugby Football League Championship when they beat Leeds 24-12 in the final. Frank Myler was awarded the Harry Sunderland Trophy as man-of-the-match.

The Challenge Cup winners were Castleford who beat Wigan 7-2 in the final.

Wigan won the Lancashire League, and Leeds won the Yorkshire League. This was the last season in which the Lancashire League and Yorkshire League titles were awarded, as the competitions were abolished following a vote on fixture reform during the season.

Challenge Cup
Castleford beat Wigan 7-2 in the final played at Wembley in front of a crowd of 95,255.

This was Castleford’s third Cup Final win in three Final appearances and their second in successive years. It was also the lowest winning score in a Challenge Cup Final at Wembley.

County cups
Swinton beat Leigh 11–2 to win the Lancashire County Cup, and Hull F.C. beat Featherstone Rovers 12–9 to win the Yorkshire County Cup.

BBC2 Floodlit Trophy
The BBC2 Floodlit Trophy winners were Leigh who beat Wigan 11-6 in the final.