This paper theoretically investigates the influence of the spatial statistic of the interferers on the performance of a millimeter-wave (mmWave) communication in line-of-sight conditions. The presented analysis, which is validated by Monte Carlo simulations, accounts for the actual transmitting/receiving antenna patterns and is based on recent mmWave channel models, which include noise, angular dispersion, mid-scale fading, and bounded path-loss. Analytical forms for the distribution of the interference-plus-noise power are derived to enable a fast and accurate computation of the capture probability when beamforming, node location, and propagation aspects must be jointly considered. The developed framework is finally used to discuss the impact of the interference density on the Shannon capacity of a mmWave uplink in realistic channel conditions.