Osteoarthritis (OA) is a chronic degenerative disease affecting articular cartilage in joints, and it is a leading cause of disability in the United States. Current pharmacological treatment strategies are ineffective to prevent the OA progression; however, cellular therapies have the potential to regenerate the lost cartilage, combat cartilage degeneration, provide pain relief, and improve patient mobility. One of the most promising sources of cellular regenerative medicine is from mesenchymal stem cells (MSCs). MSCs can be isolated from adipose tissue, bone marrow, synovial tissue, and other sources. The aim of this review is to compile recent advancement in cellular based therapy more specifically in relation to MSCs in the treatment of osteoarthritis.