Abstract: A shoulder-strap retainer attachable to a shoulder strap for preventing a shoulder strap from slipping off the user's shoulder. The shoulder strap retainer includes a main retainer body, a first retainer end, and a second retainer end. The first retainer end is axially connected to one end of the main retainer body and includes a first tongue end operatively associated with a first securing means. The second retainer end is axially connected to a second end of the main retainer body and includes a second tongue end operatively associated with a second securing means. The first retainer end is attached to one leg of the shoulder strap and the second retainer end is attached to a second leg of the shoulder strap. The shoulder-strap retainer is used such that the shoulder strap is placed on top of the shoulder while the shoulder-strap retainer is positioned underneath the arm and adjusted to securely fit the shoulder strap to the shoulder.