Forkhead box protein O3 (FoxO3a) is a forkhead box family transcription factor which serves an important role in a number of biological functions, including tumor growth. A previous study indicated that FoxO3a serves a role in insulin like growth factor-induced growth, migration and invasion of uveal melanoma (UM) cells; however, whether FoxO3a is associated with the development and formation of UM remains unknown. In the present study, the role of FoxO3a in UM development and formation was investigated by modulating the expression of FoxO3a in a human UM cell line. The results of the present study demonstrated that FoxO3a overexpression in UM cells inhibited cell proliferation and promoted cellular apoptosis, leading to an accumulation of cells at the G1 cell cycle phase. Western blot analysis demonstrated that FoxO3a overexpression increased the transcription and protein expression of Bcl-2-like protein 11 and cyclin-dependent kinase inhibitor 1B, and inhibited cyclin D1 transcription and expression. The opposite effects were observed when FoxO3a was knocked down in UM cells. The results of the present study indicated that FoxO3a may exhibit a negative role in UM development and formation, which is consistent with its role as a tumor suppressor.