A multi-band antenna has a grounding plate with a first end and a second end defined at a longer side thereof. The longer side has an upward first connecting portion adjacent to the first end and a vertical second connecting portion. A feeding portion extends downwards from a lower edge of the second connecting portion. A first antenna radiator extends towards a same direction with respect to the second connecting portion along the grounding plate from an upper side of the second connecting portion. A second antenna radiator includes a first radiating portion, a second radiating portion and a third radiating portion. A third antenna radiator extends parallel to the first radiating portion from a side of the feeding portion. A coupling component includes a first section, a second section and a third section extending opposite to the first section from an end of the second section.