To realize low-profile dual-polarized broadside radiation, a 1×8 dual-polarized low-profile slot antenna array fed by Substrate-Integrated Coaxial Line(SICL) is proposed. Unlike conventional dual-polarized arrays in which two independent feeding networks are vertically stacked, the radiating elements and the feeding network of the proposed design are arranged in the same layer, drastically reducing the overall profile. Measured results show that the array achieves a -10 dB impedance bandwidth in 25.8~27.4 GHz and an isolation higher than 20 dB. Benefiting from its simple feeding topology, low profile, and low fabrication cost, the proposed approach is highly attractive for future large-scale, high-gain, dual-polarized millimeter-wave applications.