 1. Socio-economic and health inequalities remain a major problem in post-apartheid South Africa. Despite efforts to ensure universal access to vaccines, many children are under-vaccinated in the country. 2. This study aimed to assess the prevalence and factors associated with incomplete vaccination in the first year of life among children aged 12 to 23 months in South Africa. 3. The study used a secondary. This article was authored by Dujul Ndwandwe, Djikwadi-e-Najee, Thandau-Mashuni, and others.