Social distancing behaviour is a primary preventive measure for reducing COVID-19 transmission. Improved understanding of factors associated with adherence to social distancing is vital for mitigating the impact of COVID-19 in South Africa. The study assessed adherence to social distancing and its associated factors during the state-implemented lockdown in South Africa. Data was analysed from a large-scale public survey conducted in South Africa from 8 to 29 April 2020, which was administered online and telephonically. Invitations to participate were distributed widely on local websites and social media networks, including on a data-free platform. Adherence to social distancing was measured by selfreport of having engaged in close physical contact with someone outside the home. Simple and multiple logistic regression models examined the association between social distancing and potential explanatory variables. Of the 17,586 participants, 9.2% came into close physical contact with a person outside their home by hugging, kissing, or shaking hands during the past 7 days. The odds of coming into close physical contact with other people were significantly higher for males, students, and those with incorrect knowledge on physical distancing, angry attitudes about the lockdown, lack of confidence in the government response, high-risk perception, movement out of the local area, travelling to shops using public transport, households with communal water facilities and higher household size. The 25???59-year olds compared to 18???24-year olds, and the White and Indian/Asian compared to the African population groups had significantly lower odds of close physical contact with others outside the home. The study identifies subgroups of individuals for whom public health interventions to improve adherence to social distancing should be prioritised and tailored. Interventions and policies should take cognisance of the social determinants of health as well as culturally accepted greeting practices like hand shaking.