An antenna structure includes a low frequency radiator, a high frequency radiator, and a connecting element. The connecting element has a rear end and a front end opposite to the rear end. A feeding element and a grounding element are extended from the front end of the connecting element and arranged adjacent to each other. The low frequency radiator includes a substantially inverted-L shaped first radiating part extended from the rear end of the connecting element, a meander-like second radiating part extended frontward from a front end of the first radiating part, and a substantially lying U-shaped third radiating part with a rearward opening extended from a free end of the second radiating part. The high frequency radiator includes a first extension piece extended frontward from the front end of the connecting element and located under the second radiating part with space.