This letter proposes a 2×2 surface-mount dipole antenna array based on via fence for 5G millimeter-wave applications. The dipole antenna element was first proposed, which has a compact size and low cost. Then the via fences are introduced to reduce coupling between adjacent elements and enhance isolation. In this way, compared with a 1×2 antenna array without the via fence, the isolation of a 1×2 antenna array with a via fence is improved by 12 dB at 26 GHz. The elements are extended into 2×2 arrays with and without the via fence, and their performance is evaluated by the evaluation board. The measurement results show that the -10-dB impedance bandwidth of the antenna array is 19% (24.7-29.9 GHz), and the peak gain is 9.5 dBi at 25 GHz. The proposed 2×2 array can be used in the N257 (26.5-29.5 GHz), N258 (24.25-27.5 GHz), and N261 (27.5-28.35 GHz) frequency bands. Low cost, small size, and high isolation characteristics make it one of the candidates for 5G millimeter-wave applications.