A playhouse has a main frame, a canopy mounted on and above the main frame, and two roof supporting frames. When the roof supporting frames cross each other, the canopy is propped up and expanded to construct the playhouse into a three-dimensional space. Thus, the playhouse does not collapse while children are bumping into the playhouse and is safe for use. When folding the playhouse, the roof supporting frames are inclined to overlap the main frame. Thus, the main frame and the roof supporting frames can be twisted into a figure of an “8” and then folded into a small size to reduce space that the playhouse occupies in storage.