During their preschool years, children from urban, Western populations increasingly use deception and mistrust to regulate social interactions with others who have opposing interests. The ontogeny of these behaviors in rural, non-Western populations remains understudied. This study assessed deception and mistrust within peer interactions among 4- to 8-year-old Hai||om children from rural Namibia (N = 64). Participants engaged in a dyadic game in which their self-interests were either aligned (cooperation condition) or opposed (competition condition) to those of their coplayers. Similar to previous evidence taken from Western participants, children mistrusted their coplayers during competition, but not during cooperation. Rates of actual deception were low in both conditions, which contrasts previous findings among Western populations. On an individual level, those children who deceived were also more likely to mistrust their peers. These results reveal novel insights on the ontogenetic primacy of mistrust over deception in young children's peer interactions in a rural, non-Western community.