Stacked transistors and electronic devices including the stacked transistors. An electronic device includes a substrate, a first transistor on the substrate and including a first active layer, a first gate, and a first gate insulating layer between the first active layer and the first gate, a first metal line spaced apart from the first gate on the substrate, a first insulating layer covering the first transistor and the first metal line, and a second transistor on the first insulating layer between the first transistor and the first metal line, and including a second active layer, a second gate, and a second gate insulating layer between the second active layer and the second gate.