Rates of sexually transmitted infections (STIs) are strongly associated with neighborhood poverty; however, the mechanisms responsible for this association remain unclear. Using a population-based study of sexual networks among urban African American adolescents, we tested the hypothesis that poverty, unemployment, and the sex ratio drive STI rates by affecting sexual network structure. Participants were categorized as being in one of three network positions that had previously been found to be strongly linked to infection with chlamydia and gonorrhea: being in a confirmed dyad (i.e., a monogamous pair), being connected to a larger network through one partner, and being in the center of a larger network. We found that only poverty was statistically significantly associated with sexual network position. Residing in the poorest third of neighborhoods was associated with 85% decreased odds of being in confirmed dyads. There was no association of sexual network position with neighborhood employment. Living in a neighborhood with an unequal number of young men and women appeared to be associated with a higher likelihood of being in a confirmed dyad; however, the differences were not statistically significant. These results suggest that poverty may impact STI rates by shaping sexual network structure, but we did not find any evidence that this association operates through unemployment or the sex ratio.