A garment folding apparatus serves to fold a garment while conveying the garment. The garment folding apparatus includes a loading assembly configured to load a garment, a folding assembly configured to fold the loaded garment while conveying the garment, and an unloading assembly disposed below the folding assembly and configured to unload a completely folded garment. The folding assembly includes a first conveyor configured to convey the garment in a horizontal direction, a second conveyor disposed to be spaced apart from the first conveyor in the horizontal direction, and a horizontal folding assembly including a folding bar configured to be inserted into a separation space between the first conveyor and the second conveyor, where an inclined surface of the first conveyor and an inclined surface of the second conveyor face each other, such that various horizontal folding processes are performed within a limited space.