The 2005 National League Cup (known for commercial reasons as the Northern Rail Cup) was a British rugby league competition.
The 2005 competition was the first to feature sides from National League Three: previously the competition had only featured sides from National Leagues One and Two.
The top team from each of the first five groups progressed to the quarter-final directly.
The second-placed team in each of these groups, plus the top team from group six (the group of teams from National League 3), played an additional round to determine the remaining three spots in the quarter-finals.
The winners of the 2005 Northern Rail Cup were Hull Kingston Rovers.