A surgical stapling device that comprises an end effector. According to various embodiments, the end effector comprises a circular anvil having a staple forming surface and a plurality of staples facing the staple forming surface of the anvil. The end effector also comprises a staple driver assembly comprising a plurality of staple drivers. Each staple driver supports one of the plurality of staples and is configured such that, when the staple driver assembly is actuated, each staple driver drives the staple into the staple forming surface of the anvil. A first quantity of the plurality of staple drivers has a first height and a second quantity of the plurality of staple drivers has a second height, wherein the first height is less than the second height.