Abstract: A finger ring fitting aid is attached readily to a finger ring and has a sizing member selectively movable between a first position, wherein the sizing member lies outside the finger ring opening to enable unrestricted access to the opening for placement of the ring on a wearer's finger, and a second position, wherein the sizing member lies inside the finger ring opening to constrict the opening to a desired fitted size. A resilient biasing mechanism biases the sizing member into either one of the first and second positions such that movement of the sizing member to either position and retention of the sizing member in either position is accomplished with ease and without requiring any auxiliary tool.