Disclosed are a 3 dB orthogonal hybrid coupler, a radio-frequency front-end module and a communication terminal. The 3 dB orthogonal hybrid coupler can be arranged on a substrate, and a straight-through metal coil and a coupling metal coil are of a laminated structure, a coplanar structure or a combined form of the laminated structure and the coplanar structure, such that a corresponding radio-frequency signal input port is connected to a first radio-frequency signal output port, and an isolation port is connected to a second radio-frequency signal output port. Moreover, according to the requirements of the operating frequency and the port feature impedance of the 3 dB orthogonal hybrid coupler, the number of turns and the number of layers of the straight-through metal coil and the coupling metal coil are adjusted.