This study proposes a novel design of monolithic compliant variable torsional stiffness (VTS) mechanism whose stiffness can be tuned continuously. This mechanism is then used to create a compliant variable stiffness (VS) ball joint. This compliant VS ball joint can be beneficial in various applications such as exoskeletons, prostheses, and bio-mimicking due to their high adaptability to environmental changes and the capability for multitasking.