The elbow has always been a difficult joint to manage because of the subtle nuances of pathology, examination, and treatment. Patients experiencing the sequelae of recurrent elbow instability can lose a substantial amount of function in the affected upper extremity. Elbow instability comprises a wide spectrum of disease ranging from valgus instability in the throwing athlete to traumatic recurrent rotatory instability to iatrogenic damage. Our goal in this article is to provide readers with information to guide them in the development of a systematic algorithm for the treatment of a variety of elbow instability problems. First, we will discuss basic elbow biomechanics and their alterations in the unstable elbow. Next, a thorough discussion of the history, physical examination, and imaging studies necessary to diagnose these injury patterns will be presented. Finally, we will discuss the nuances in the treatment of both medial/valgus elbow injuries and posterolateral rotatory instability of the elbow. Cutting-edge advances in surgical reconstruction of the unstable elbow will allow those caring for these difficult injuries to make the proper management decisions.