The 1915 Wigtownshire by-election was held on 12 February 1915. The by-election was held due to the incumbent Conservative MP, John Dalrymple, succeeded as the 12th Earl of Stair. It was won by his uncle, the Conservative candidate Hew Hamilton Dalrymple,^[1] who was unopposed.

At the time of the election, John Dalrymple was a prisoner of war in Germany, having been captured by the Germans during the Great Retreat in 1914. He remained a prisoner until 1917 when he was repatriated for medical reasons, due to degradation in his eyesight.^[2]