Adverse pregnancy outcomes are an important indicator of the overall health of a population and the socioeconomic development of a country. To determine the prevalence and factors associated with adverse pregnancy outcomes among women of reproductive age in South Africa, and to recommend strategies to reduce the burden of these outcomes. We conducted a secondary data analysis on women of reproductive age using data from the nationally representative, population- based, cross-sectional 2016 South Africa Demographic and Health Survey (SADHS). We described the sociodemographic characteristics of the study participants and determined the prevalence and factors associated with adverse pregnancy outcomes using the multivariable logistic regression model. We adjusted all our analyses for complex survey sampling using survey weights. There were 8 514 women of reproductive age, of whom 41.2% had fallen pregnant during the 5-year period preceding the survey. The majority (70.9%) were of age 20 - 34 years, 78% had secondary education, 61.6% were unemployed, 65% were from urban areas, and more than 40% of these women were currently living with a man, while 51.5% reported that they had never been in a union. The prevalence of adverse pregnancy outcomes was 14.6% (95% CI 13.2 - 16.1%). The odds of experiencing adverse pregnancy outcomes were significantly higher for those aged 35 - 49 years (adjusted odds ratio (aOR) 7.41, 95% CI 3.46 - 15.85) or 20 - 34 years (aOR 2.07, 95% CI 1.02 - 4.18), compared with those aged 15 - 19 years. Women who were currently in a union/living with a man (aOR 1.85, 95% CI 1.41 - 2.43) or formerly in a union/living with a man (aOR 2.66, 95% CI 1.64 - 4.29), compared with those who had never been in a union, had higher odds of adverse pregnancy outcomes. Contrarily, adverse pregnancy outcomes were lower with each additional child delivered or ever born (aOR 0.66, 95% CI 0.58 - 0.75). We report a high prevalence of adverse pregnancy outcomes among women of reproductive age in South Africa. We recommend addressing factors such as maternal age and currently/formerly living with a man within interventions to reduce the burden of adverse pregnancy outcomes in South Africa.