Abstract: A collar that fits on the bar of a barbell to prevent weights from sliding off the bar. Two semi-circular sections of the collar are hinged together at one end of the sections to permit closure of the sections about the bar and a toggle linkage is mounted on the other ends of the section to hold the collar closed about the bar. Neoprene pads are affixed to the inner peripheries of the sections to grip the bar and prevent movement of weights thereon when the collar is mounted on the bar. The collar can be mounted on the bar or removed therefrom without moving the collar over the end of the bar so that weights can be placed on the bar while the collar is in place and subsequently secured by moving the collar and a weight can be removed from the bar by moving the collar to a position in which the weight is between the collar and the end of the bar prior to moving the weight off the end of the bar.