An immobilizing sleep garment assembly includes a vest is wearable on a user when the user is recovering from shoulder surgery. A plurality of chest mating members is each vertically oriented on the vest. A plurality of first straps is each disposed on the vest and a plurality of second straps is each of the second straps is disposed on the vest. Each of the first straps is releasably matable to a respective one of the second straps to secure the vest around the user's upper torso. A glove is provided that can be worn on a respective one of the user's hands. A glove mating member is coupled to the glove and the glove mating member releasably engages the chest mating members at a desired location on the plurality of chest mating members to restrain the user's arm for sleeping while recovering from the shoulder or arm surgery.