Malfunctions of a circuit is prevented and the reliability of a semiconductor device using the circuit is improved. The semiconductor device includes a first transistor, a second transistor, a load, and a wiring having a function of supplying a power supply potential to the load. A semiconductor layer of the first transistor includes an oxide semiconductor. A semiconductor layer of the second transistor includes an oxide semiconductor. A source and a drain of the first transistor are electrically connected to the wiring. A first gate of the first transistor is supplied with a reference potential. A source and a drain of the second transistor are supplied with the reference potential. A first gate of the second transistor is electrically connected to the wiring. The semiconductor layer of the first transistor includes a region overlapping with the wiring. The semiconductor layer of the second transistor includes a region overlapping with the wiring.