Disclosed are stent delivery apparatus and methods for moving a balloon catheter carrying a stent through a body vessel without the stent slipping from the balloon are provided. In general, the stent delivery system includes a stent stopper that impedes the stent from slipping from the balloon. The stent stopper is sized to serve as a barrier to the stent as it is carried on the balloon. In a specific embodiment, the stent stopper is formed from a material that encircles the proximal end of the balloon and abuts the proximal end of the stent. The stent stopper material expands with expansion of the balloon and collapses with deflation of the balloon. In some embodiments, the stent stopper material has a thickness that is about equal to or greater than the thickness of the stent so as to form a barrier against the stent and impede the stent from slipping off the proximal end of the balloon.