A novel planar end-fire circularly polarized (CP) complementary antenna is presented. It consists of an aperture element as the magnetic dipole and a printed dipole element as the electric dipole. Due to the combination of the vertically polarized component from a magnetic dipole and the horizontally polarized component from a printed dipole on the same substrate, a planar CP antenna with end-fire beam in parallel with its plane is achieved. The operation principle is analyzed and the prototype is then fabricated and measured for validation.