Abstract: A sport boot is provided that is suitable for, but not limited to, use as a snowboard boot. The sport boot includes an outer shell and an inner liner received within the outer shell. The outer shell includes an outsole and a protective upper affixed to the outsole. The inner liner includes a cushioning midsole and a flexible upper affixed to the midsole. Unlike conventional sport boots that place the midsole between an insole board and a shank on the outer shell, the present invention incorporates the midsole onto the inner liner directly under a rider's foot to provide a level and more stable platform. With the midsole built into the inner liner, there is an improved relationship between the horizontal plane a rider's foot lies in and the horizontal plane of the midsole. When attached in this manner, a rider's foot and the midsole more effectively remain in parallel planes, which improves the overall comfort and performance of sport boot.