An illumination system including a first light emitting chip, a chip package, a first dichroic film, and a second dichroic film is provided. The first light emitting chip emits a first light beam. The chip package includes a second light emitting chip and a third light emitting chip. The second light emitting chip emits a second light beam. The third light emitting chip emits a third light beam. The colors of the first, second, and third light beams are different from each other. The first dichroic film is disposed in the transmission paths of the first and second light beams. The second dichroic film is disposed in the transmission paths of the first, second, and third light beams. The first and second dichroic films are not parallel to and do not intersect each other. Besides, a projection apparatus employing the illumination system and another projection apparatus are provided.