An antenna with double groundings, including a body part, a feeding part, a first grounding part, and a second grounding part, is provided. The body part is electrically connected to the feeding part, the first grounding part, and the second grounding part respectively. The body part is corresponding to a resonance length to transmit and receive a radiation wave with a wavelength at an operating frequency. Wherein, a current path from the first grounding part to the feeding part along the body part is ½ times of the wavelength at the operating frequency, and a relative distance between the second grounding part and the first grounding part is ¼ times of the wavelength at the operating frequency.