Abstract: A playhouse for cats including a housing having panels that are formed in a one-piece construction and that are movable relative to each other to a closed collapsed position, whereby the housing is conveniently stored or shipped, a plurality of interior deck members being located within the housing to define a plurality of spaced interior compartments, openings being formed in the vertical panels which communicate with the interior compartments to provide access thereto for a cat, and a locking construction for retaining the vertical panels in the open erected position and that includes locking flap assemblies that are joined to the vertical panels at the uppermost ends thereof and that are foldable to a locked position to define horizontal upper perimeter rampart segments for securing the vertical panels in a stable erected position.