A deposition apparatus includes a chamber, a deposition source, and a stage disposed in the chamber with a target object mounted thereon. The deposition apparatus further includes a first plate coupled to the chamber, and a second plate disposed between the first plate and the stage, wherein the second plate includes a plurality of diffusion holes. The deposition apparatus additionally includes a heat dissipation member in contact with the first plate and the second plate, wherein the heat dissipation member includes a plurality of sidewall portions, wherein the plurality of sidewall portions are connected to each other. The deposition apparatus further includes a spacer coupled to a first sidewall portion of the plurality of sidewall portions and disposed between the first plate and the second plate, wherein the spacer extends parallel to the first sidewall portion.