This communication proposes a dual-polarized end-fire phased array for 5G handset devices at 28 GHz. The proposed four-element array has low profile of 1.1 mm, small clearance of 2.7 mm, and symmetric patterns in the vertical plane. The array element is fed by substrate-integrated waveguide (SIW), which works as a waveguide (WG) antenna with vertically polarized radiation pattern. Two transition plates are introduced to improve the impedance matching of the WG antenna. The horizontal polarization is generated by exciting one of the transition plates as an antenna. The other transition plate is modified as a group of triangle strips to minimize its reflection to the horizontal radiation patterns. A −10 dB frequency bandwidth of 5.3% and a −6 dB bandwidth of 25% are achieved, overlapping between the vertical and horizontal polarization. The array scanning angle is from −54° to 44° at 29 GHz for both polarization. Within the scanning range, the end-fire gain varies from 7.48 to 8.14 dBi for the horizontal polarization, whereas from 4.49 to 8.05 dBi for the vertical polarization. Good agreements between simulations and measurements are well achieved and shown in this communication.