Otto Bache (21 August 1839 – 28 June 1927) was a Danish Realist painter.

At age eleven he received a dispensation and was admitted into the Royal Danish Academy of Fine Arts, studying under Wilhelm Marstrand, among others.

His stay in Paris had a particularly deep impact on his work, turning it in a direction characterized by more freedom, more colour, stronger light, and broader scope.

He was named a Commander in the Order of the Dannebrog and later was awarded the Dannebrogordenens Hæderstegn.

He received early recognition as a portrait painter but he also showed great interest in painting animal motifs, gradually also turning to genre works and history painting.