Kit foxes (Vulpes macrotis) are nocturnal, monogamous, and territorial. We used telemetry to monitor nocturnal interactions of pair members with each other and neighboring foxes in central California during 1989–1991. Observed distances between mated foxes consistently were closer than expected by chance. This positive association probably resulted from a tendency for foxes to move around common den or foraging sites; mates did not exhibit concordant movement patterns. Nocturnal encounters probably are not necessary to maintain pair bonds because mates regularly share dens during the day throughout the year. Encounters may be more important during pair formation because members of recently formed pairs encountered each other more frequently (>16% of locations) than did established pairs (<13% of locations). Observed distances between neighboring foxes were not consistently closer or further apart than expected by chance, and encounters were rare (<2% of locations). Hence, direct interactions between neighboring foxes may be relatively unimportant for maintaining established territories. However, 2 male mated kit foxes trespassed into neighboring territories during the breeding season, probably in search of extra-pair copulations.