The 1905–06 Challenge Cup was the 10th staging of rugby league's oldest knockout competition, the Challenge Cup.
Intermediate round
The intermediate, or qualifying, round matches were played on 17 February 1906. Replays The two replays were played on 24 February 1906. ==First round==
First round
Replay The replayed fixture was played on 7 March 1906. ==Second round==
Second round
Second round fixtures were played on 17 March 1906. Replay ==Third round==
Third round
The third round fixtures were played on 31 March 1906. Replays The two drawn matches were replayed the following week. Halifax played Bradford on 3 April with Broughton Rangers v Salford played on 4 April. The Broughton v Salford tie required a second replay to decide the fixture and this was played at Wigan on 6 April. ==Semi-finals==
Semi-finals
The semi-finals were played at neutral venues on 14 April 1906. ==Final==