[Purpose] Gluteus medius syndrome is one of the major causes of back pain or leg pain and is similar to greater trochanteric pain syndrome, which also presents with back pain or leg pain. Greater trochanteric pain syndrome is associated with lumbar degenerative disease and hip osteoarthritis. The objective of this review was to demonstrate gluteus medius syndrome as a disease entity by reviewing relevant articles to elucidate the condition. [Methods] Gluteus medius syndrome was defined as myofascial pain syndrome arising from the gluteus medius. We performed a search of the literature using the following keywords: "back pain", "leg pain", "greater trochanteric pain syndrome", "degenerative lumbar disease", "hip osteoarthritis", and "gluteus medius". We reviewed articles related to gluteus medius syndrome and described the findings in terms of diagnosis and treatment based on the underlying pathology. [Results] A total of 135 articles were included in this review. Gluteus medius syndrome is similar as a disease entity to greater trochanteric pain syndrome, which presents with symptoms of low back pain and leg pain. Gluteus medius syndrome is also related to lumbar degenerative disease, hip osteoarthritis, knee osteoarthritis, and failed back surgery syndrome. [Conclusion] Accurate diagnosis of gluteus medius syndrome and appropriate treatment could possibly improve lumbar degenerative disease and osteoarthritis of the hip and knee, as well as hip-spine syndrome and failed back surgery syndrome.