Popliteal (Baker) cysts, meniscal cysts, proximal tibiofibular joint cysts, and cruciate ligament ganglion cysts are cystic masses commonly found about the knee. Popliteal cysts form when a bursa swells with synovial fluid, with or without a clear inciting etiology. Presentation ranges from asymptomatic to painful, limited knee motion. Management varies based on symptomatology and etiology. Meniscal cysts form within or adjacent to the menisci. These collections of synovial fluid are thought to develop from translocation of synovial cells or extravasation of synovial fluid into the meniscus through a tear. Joint-line pain and swelling are common symptoms. Management entails partial meniscectomy with cyst decompression or excision. Proximal tibiofibular joint cysts are rare, and their etiology remains unclear. Pain and swelling secondary to local tissue invasion is common, and management consists of surgical excision. Cruciate ligament ganglion cysts have no clear etiology but are associated with mucoid degeneration of the anterior and posterior cruciate ligaments, knee trauma, and synovial translocation into these ligaments. Knee pain and limited range of motion, especially with exercise, are common presenting symptoms. In symptomatic cases, arthroscopic excision is commonly performed.