The semimagnetic semiconductor MnGa2Se4 is a direct energy gap material (Eg = 2.7 eV at 300 K) crystallizing in the tetragonal structure, space group I4-. In this paper, the optical absorption edge of MnGa2Se4 was measured as a function of pressure up to 13 GPa. The measurements were performed in a diamond-anvil cell at ambient temperature using a 4:1 mixture of methanol and ethanol as pressure-transmitting medium. The direct energy gap (Γv13 → Γc11) increases linearly with pressure at the rate of 2.5 × 10—2 eV GPa—1. At 4.1 GPa the character of the fundamental gap changes to pseudodirect (Γv13 → Γc23). This direct gap decreases with pressure at the rate of —4.6 × 10—2 eV GPa—1. The absorption band at energies below the direct gap is attributed to manganese 6A1 → 4T2 intraionic transitions and shows a red shift under pressure. A first-order structural phase transition was observed at 12.8 GPa in the upstroke. (The samples turn black when observed visually under a microscope.)