The long non-coding RNA MFI2 antisense RNA is overexpressed in human cancer tissues and its increased expression is associated with occurrence and metastasis of cancer. However, the underlying mechanism in evolution and progression of human osteosarcoma is not well known. In the present study, we aimed to evaluate the molecular mechanism of lncRNA MFI2 in promoting osteosarcoma cell proliferation and suppressing apoptosis. We found that the lncRNA MFI2 was significantly overexpressed in human osteosarcoma tissues. Knockdown of lncRNA MFI2 expression suppressed MG63 and SAOS-2 cell proliferation, migration and invasion, and induced cell apoptosis. Furthermore, the expression of forkhead box P4 (FOXP4) was significantly increased and it was positively associated with lncRNA MFI2 expression in tumor tissues. In addition, knockdown of FOXP4 expression by RNA interference strategy inhibited osteosarcoma cell proliferation, migration and invasion, and promoted cell apoptosis. All the results indicated lncRNA MFI2 could promote proliferation and migration of osteosarcoma cells by regulating FOXP4 expression, which suggested critical roles of lncRNA MFI2 and FOXP4 in occurrence and development of human osteosarcoma.