An electronic device may include a first housing configured to slide with respect to the second housing, a second housing receiving at least a portion of the first housing, a display configured to be unfolded based on sliding of the first housing, a motor structure configured to generate a driving force for the sliding of the first housing, the motor structure disposed on the second housing, and a gear assembly including a first gear connected to the motor structure, a rack gear connected to the first housing and configured to slide along with the first housing, a second gear configured to mesh with the rack gear, and a third gear connected to the second gear and configured to rotate based on rotation of the first gear.