An integrated fan-out package having a multi-band antenna and a method of forming the same are disclosed. An integrated fan-out package includes a semiconductor die, a molding layer and a plurality of through integrated fan-out vias. The molding layer is aside the semiconductor die. The through integrated fan-out vias are through the molding layer and arranged to form a plurality of dipole antennas. At least one of the plurality of dipole antennas includes two dipole arms each having a transmitting strip and a radiating strip connected to the transmitting part, and the radiating strip has a first part, a second part and a filter part between and in contact with the first part and the second part. The cross-sectional area of the filter part is less than the cross-sectional area of the first part or the second part of the radiating strip.