An orthopedic device for improving posture while sitting, having a foundation member including a front portion for upper legs and a bowl portion for lower pelvic area. The bowl portion has a central portion and an upwardly inclined lateral portion. The lateral portion and the front portion collectively surround the central portion. The central portion has regions of varying flexibility and the lateral portion has regions of varying flexibility. The bowl portion applies an upwardly and inwardly compressive force when the lower pelvic area is disposed in the bowl portion, and rotates on a supporting surface between a first position when the lower pelvic area is not disposed in the bowl portion, and a second position, rotationally forward of the first position, when the lower pelvic area is disposed in the bowl portion, to thereby cause a forward rotational tilting of the lower pelvic area into a forward lordotic position after the lower pelvic area is placed in the bowl portion.