In this paper, a wideband dual-polarized full-duplex antenna array is presented. The array is formed of four dual-polarized Vivaldi antennas with a modified feeding to obtain total symmetry between the orthogonal polarizations. The array is fed by a wideband 4-way balun that can split the input signal into four output signals of equal amplitudes with two of them being phase inverted with respect to the other two. The simulated results indicate that the array is matched from 2 GHz to beyond 20 GHz with an average gain of 11 dBi. Also, under ideal conditions, the array can achieve a high level of self-interference cancellation (≥120 dB), and this level is estimated to be better than 40 dB in practice.