<p>: Decisions regarding sexual and reproductive health significantly impact women’s health and their protection against HIV/AIDS and other sexually transmitted infections. These decisions also impact females’ ability to reach their reproductive goals. Women’s autonomy is recognized to be vital to women’s access to reproductive healthcare, the use of contraceptives, the capacity to avoid or receive treatment for STIs (including HIV), and other reproductive and sexual health issues. This research investigated the association between the decision-making power of South African women (of reproductive age) and their knowledge and practices regarding HIV/AIDS preventive measures. The present study used data from the South Africa Demographic and Health Survey 2016. A total of 8514 women aged 15–49 years who participated in the survey were used for this research. The mean age of the women was 30.21 years, with an SD of 9.86. Approximately 38.5% of the women decided on contraceptive use, and only 11.7% of women’s partners and 49.8% of respondents were jointly involved in the decision-making process of contraceptive use. All HIV preventive measures under study were statistically significantly associated with high decision-making power; the use of a condom by the husband or partner of the women was the most significant; husbands or partners of the women with high autonomy were three times more likely to use condoms.</p>