The 1939–40 Northern Rugby Football League season was an emergency season of English rugby league fixtures necessitated by the outbreak of the Second World War. The regular league season had started at the end of August 1939, but on the outbreak of war all sport was suspended. When government permission for sport to be resumed was given, the league was reorganised into two regional competitions, Yorkshire and Lancashire. The winners of each league playing against each other to decide the overall champions. The Yorkshire competition was won by Bradford Northern who beat Swinton, winners of the Lancashire competition, in the two-legged league final.

The season also saw the resumption of County Cup competition, as well as some representative matches arranged to raise funds for the British Red Cross. The Challenge Cup competition, traditionally run alongside the league, was not played for the first time since 1919.

1939–40 Northern Rugby Football League Wartime Emergency League season

Planned season

The planned 1939–40 season had begun as scheduled on Saturday 26 August 1939 with 27 clubs starting the season. This was one less than the previous season as St Helens Recs had disbanded at the end of the 1938–39 season. The withdrawal of St Helens Recs required a change in the way fixtures were organised. With 28 clubs in the league, each club was a member of the 14 team Lancashire League or the 14 team Yorkshire League. The actual geographical split of clubs was 15 clubs based in Yorkshire and 13 in Lancashire, so Halifax played as a member of the Lancashire League. Each teams' fixture list comprised a home and away fixture against all the teams in their county league (26), as well as home and away fixtures against seven teams in the other county league (14) for a total of 40 games.

1939–40 Northern Rugby Football League Wartime Emergency League season

With only 27 clubs the League's secretary, John Wilson, proposed a 36-game season for each club with Halifax remaining in the Lancashire league, and Dewsbury, who were the lowest finishing Yorkshire team in the previous season, playing as a member of neither county league. For the purposes of determining fixture lists Dewsbury would be considered the 14th team of both county leagues. Excepting Dewsbury, each team's fixture list would comprise the other teams in their own county league (24 games) together with six teams from the other county (12 games). Dewsbury's opponents would be nine clubs from each county.

1939–40 Northern Rugby Football League Wartime Emergency League season

At the League's annual general meeting on 7 June 1939 the clubs accepted Wilson's proposal regarding the positions of Halifax and Dewsbury, but voted for a 40-game fixture list instead of Wilson's 36 game proposal. The fixture lists were issued later in June. Each team, except Dewsbury, had home and away fixtures against all the teams in their own county league (24 games). They also had home and away fixtures against eight teams in the other county league (16 games). Dewsbury's fixture list comprised home and away fixtures against 10 teams from each county league.

A full programme of games was played up to Saturday 2 September. By that date most clubs had played two or three games as some clubs had played midweek matches.

Suspension of the League

On Monday 4 September the day after the declaration of war, all rugby league games and all other spectator sports and public entertainments were suspended by provisions of the Prohibition of Public Entertainments (Defence) Order, one of numerous orders made following the enactment of the Emergency Powers (Defence) Act 1939. As a result, some clubs like Wigan and Salford announced they were closing for the duration of the war and that their players were released.

One issue clubs had to consider was what to do with the monies paid for season-tickets, the holders of which may have only seen one or two games. Barrow, for one, resolved to repay season-ticket holders less a deduction for games seen, while Oldham decided not to give any refunds stating, "We are up against it and must appeal to our members to make this sacrifice".

Under the defence regulations and air raid precautions, all areas of the country were designated as evacuation, neutral or reception areas depending on the assessment of an area as an enemy target and its ability to receive people from the evacuation areas. The defence regulations allowed for the resumption of sporting events within reception or neutral areas and on 9 September the Home Secretary issued the Public Entertainments (Restriction) Order allowing events to go ahead outside evacuation areas. Attendances were limited to 8,000 or 15,000 at grounds with a capacity over 60,000.