An antenna structure including a first radiator and a second radiator is provided. The first radiator includes a first segment, a second segment, a third segment, and a fourth segment all bent to be connected in sequence, in which the first segment includes a feed-in terminal. The second radiator includes a fifth segment, and a sixth segment, a seventh segment, an eighth segment, and a ninth segment which are connected respectively to the fifth segment, in which the fifth segment is located beside the first radiator while a first slit is formed between the first radiator and the fifth segment of the second radiator, the sixth segment includes a ground terminal, and the first radiator and the second radiator are adapted to couple to form a first frequency band, a second frequency band, a third frequency band, and a fourth frequency band.