An antenna module includes a substrate and an antenna structure. The antenna structure is disposed on the substrate and includes a radiating portion, a feeding portion, a ground plane, and an impedance adjustment portion. The feeding portion is coupled to the radiating portion and the ground plane. The impedance adjustment portion has a connection end portion and a ground end portion opposite to each other. The connection end portion is connected to the radiating portion. The impedance adjustment portion is bent relative to the radiating portion to extend from the connection end portion toward the feeding portion along an extending direction. The ground end portion is connected to the ground plane and near the feeding portion. In addition, an electronic device including the antenna module is also provided.