Synovial cyst of the proximal tibiofibular joint is a very rare condition, for which there is no consensus regarding treatment. Two macroscopic forms may be encountered: extraneural cysts and intraneural cysts. We present the cases of two patients who had synovial cysts of proximal tibiofibular joint that caused peroneal nerve palsy. We discussed the special features of synovial cysts and reviewed the literature. We considered the best treatment of synovial cysts originating from proximal tibiofibular joint and causing peroneal nerve palsy to be a total surgical removal as soon as possible after the diagnosis is made. However, follow-up is needed because recurrence is possible. It should be kept in mind that despite surgical treatment the neurological symptoms may not recover.