A pet co-sleeper is designed to be connected to a human's bed for use by small to medium sized animals. Pets such as dogs and cats can use this sleeper to sleep beside their owners instead on of the bed. The pet co-sleeper has a frame which is substantially rectangular in shape. The frame has three horizontal bars forming a three-sided top frame and a fourth horizontal bar on the fourth side is lower than the other three horizontal bars. Fabric materials attached to the frame form a floor, four side walls and a horizontal divider located just below the fourth horizontal bar. A first mattress is placed over the horizontal divider to form a sleeping surface. A second mattress is placed on the fabric floor, such that the four side walls, the second mattress and the horizontal divider form a pet house.