A valve assembly for a leak resistance drinking cup is selectively configurable between a sealed position and an unsealed position. The valve assembly includes a plug having an inner surface, an outer surface, and an opening extending through the plug from the outer surface to the inner surface. An amount of vacuum acting on the outer surface of the plug needed to move the valve assembly from the sealed position to the unsealed position is less than the amount of internal pressure acting on the inner surface of the plug needed to move the valve assembly from the sealed position to the unsealed position.