Osteoarthritis (OA) is the most frequent degenerative progressive joint disease worldwide, with the hand, hip, and knee being the most-affected joints. Actually, no treatment can alter the course of OA, and therapy is directed at reducing pain and improving function. The exogenous administration of collagen has been investigated as a possible symptomatic adjuvant or stand-alone treatment for OA. The aim of this review is to assess if intra-articular collagen administration can be considered as a valid and safe therapeutic option for OA. A search in the main scientific electronic databases to identify the available scientific articles about the effects of intra-articular collagen as an OA treatment was performed. The results of the seven included studies showed that the intra-articular administration of collagen may stimulate chondrocytes to produce hyaline cartilage and hinder the normal inflammatory response leading to fibrous tissue formation, reducing symptoms, and improving functionality. The use of type-I collagen as an intra-articular treatment for knee OA was found not only to be effective, but also safe with negligible side effects. The reported findings are strongly promising, highlighting the need for further high-quality research to confirm the consistency of these findings.