Semiconductor devices may include a first semiconductor chip, a first redistribution layer on a bottom surface of the first semiconductor chip, a second semiconductor chip on the first semiconductor chip, a second redistribution layer on a bottom surface of the second semiconductor chip, a mold layer extending on sidewalls of the first and second semiconductor chips and on the bottom surface of the first semiconductor chip, and an external terminal extending through the mold layer and electrically connected to the first redistribution layer. The second redistribution layer may include an exposed portion. The first redistribution layer may include a first conductive pattern electrically connected to the first semiconductor chip and a second conductive pattern electrically insulated from the first semiconductor chip. The exposed portion of the second redistribution layer and the second conductive pattern of the first redistribution layer may be electrically connected by a first connection wire.