Although hypertension is a significant public health burden in South Africa (SA), less is known about its prevalence, risk factors, and possible preventative strategies among young adults. We assessed the prevalence, possible risk factors, and knowledge associated with self-reported hypertension among young adults from SA. A cross-sectional online survey was conducted among 1000 young South African adults (24-40 years
51.0% women). We administered a socio-demographic questionnaire and collected information on measures of socio-economic status (SES) (e.g. asset wealth index), self-reported medical history, and lifestyle risk factors. Furthermore, a modified version of the hypertension evaluation of lifestyle and management questionnaire was used to assess participants' hypertension knowledge. The overall prevalence of self-reported hypertension was 24.0%, with significant differences between women and men (27.5% and 20.4% respectively, p = 0.033). Only 16.8% of the respondents had good hypertension knowledge. There was a positive association between good knowledge of hypertension and being hypertensive (OR = 1.43 CI:1.23-3.12), monthly blood pressure check-ups (OR = 2.03 CI:1.78-3.23), knowing the side effects of uncontrolled blood pressure (OR = 1.28 CI:1.07-1.89) and having a biological mother with hypertension (OR = 1.79 CI:1.53-2.21). Being employed full-time (OR = 0.74 CI:0.69-0.80), having a higher SES (wealth index 4 (OR = 0.70 CI:0.59-0.97) and 5 (OR = 0.65 CI:0.48-0.81)), exercising 6 to 7 days per week (OR = 0.83 CI:0.71-0.94), and not consuming alcohol at all (OR = 0.73 CI:0.67-0.89), were all found to be protective against hypertension. The high hypertension prevalence, lack of hypertension knowledge, and reported risk factors among this group highlight the need for early robust preventative strategies to mitigate hypertension risk among this population.