Portrait of an Army Doctor is an oil-on-canvas painting created during 1914–15 by the French artist, theorist and writer Albert Gleizes. Painted at the fortress city of Toul (Lorraine) while Gleizes served in the military during the First World War, the painting's abstract circular rhythms and intersecting aslant planes announce the beginning of the second synthetic phase of Cubism. The work represents Gleizes's commanding officer, Major Mayer-Simon Lambert (1870–1943), the regimental surgeon in charge of the military hospital at Toul. At least eight preparatory sketches, gouaches and watercolors of the work have survived, though Portrait of an Army Doctor is one of Gleizes's only major oil paintings of the period.