Osteochondrosis (OC) is a frequent manifestation of developmental orthopaedic disease, and its several clinical presentation is kwon as OC dissecans (OCD). OC is defined as a disruption of the endochondral ossification process in the epiphyseal cartilage and this disease has been reported in different mammalian species, including human, dogs, pigs, and horses. OCD is one of the most relevant problems in the equine industry, which has been regarded as an important cause of lameness in sport horses. In fact, OCD is the predominant cause of impaired orthopaedic potential, whose symptoms may be of minimal magnitude or manifest as severe joint effusion or clinically noticeable lameness. The aetiology of OCD is unknown, although it has traditionally been considered a multifactorial pathology. Among the associated factors have been included non-genetic factors as rapid growth, nutrition, trauma and anatomic conformation, and genetic factors. Since the prevalence of the disease varies greatly depending on the horse breed, from 13% in Swedish Warmblood to 53% in Lusitano breed, it seems that genetic factors have a great relevance in the appearance and development of OCD in horses. In fact, many genetic modifications have been related, and the genes involved can be grouped into five clusters, which involves fundamental functions for the correct development and regeneration of cartilage, such as collagen, laminin, cell signalling, matrix turnover and transcription regulation. This review summarizes the main factors associated with OC in horses, with special relevance to genetic factors.