Philaeus may refer to:
In Greek mythology: Philaeus (son of Ajax), a son of Ajax and Lysidice Philaeus, a son of Munichus and Lelante
In biology: Philaeus, a spider genus Philaeus chrysops, a species in this genus Philaeus multicolor, a synonym for Paraphidippus aurantius Philaeus farneus, a synonym for Phidippus audax