Abstract: A locking mechanism in combination with a buckle connecting the separate straps of a horse blanket. A buckle includes a T-shaped coupling and a curved U-shaped coupling which couple together to form the buckle. The strap lock itself is comprised of a flat rectangular plate which has one end folded back onto itself to form a flange member, a base and a hollow cavity at the bight of the flange. The base contains raised projections which act as stops for preventing the loss of the strap lock. The strap lock is made of a resilient material because as it is being forced into its locking position, the bight of the flange member has to spread apart enough to slide over the curved area of the U-shaped coupling. The edge of the flange member confronts the head of the T-shaped coupling and prevents the T-coupling from sliding forward and twisting and uncoupling the buckle.