A modeling study evaluates the impact of socioeconomic status and economic empowerment interventions on the incidence of HIV, sexually transmitted infections (STIs), and adolescent births in South Africa. Low socioeconomic status contributed to 13% of new HIV infections, 7% of STI incidents (gonorrhea, chlamydia, trichomoniasis) and 31% of adolescent births in 2000–2020. The study extended the existing model of HIV, STIs and fertility, estimating the effects of education, employment and income on sexual behavior based on the literature and randomized trials. Interventions considered for households below the national median income included school dropout support, vocational training for the unemployed and unconditional cash transfers. In the period 2025–2040, no intervention will significantly reduce these problems, with school support having the greatest effect on teenage births (5% reduction, 95% CI: -1.12%). Confidence intervals around attributable population fractions are wide (1.50% for HIV, -1.19% for STIs, 10.76% for teenage births). Major limitations include the assumption of equal access to STI treatment across socioeconomic strata and the exclusion of community effects. Poverty is a significant cause of these problems, but tested interventions do not have sufficient impact on the population.