The utility model provides an auxiliary frame for a
bathtub and a
bathtub assembly, the auxiliary frame comprises a first rod part, a second rod part and a third rod part, the two opposite ends of the first rod part are detachably connected to the two side walls of the
bathtub; the top end of the second rod part is connected to the first rod part, and the first rod part, the second rod part and the bottom of the bathtub form at least one through hole through which the legs of an infant penetrate. The auxiliary frame is connected to the bathtub, so that the auxiliary frame and the bottom and the side wall of the bathtub can form a space capable of just accommodating a child, and the child can keep a
sitting posture in the
bathing process.