HIV and AIDS continue to pose a global health and development challenge, particularly in sub-Saharan Africa. South Africa has the largest number of people living with HIV (PLHIV) in the world. In spite of the accelerated efforts to combat the HIV and AIDS epidemic, there still remains an unabated challenge, i.e. continuing new infections, particularly among young African adults. HIV is largely transmitted through unprotected vaginal and anal sexual intercourse. This study sought to unpack the meaning of ukujola (casual or informal sexual relationships) as socially constructed by Zulu people, and to identify underlying socio-economic factors for ukujola. This study uses a generic qualitative study approach in which 32 qualitative interviews (4 focus groups, 20 in-depth interviews and 8 key-informant interviews) were conducted with isiZulu-speaking participants (aged 21–34) from Umgungundlovu district, KwaZulu-Natal province. The study found that ukujola relationships are a relatively new phenomenon in Zulu society. Ukujola relationships encompass all “illegitimate” relationships, i.e. in which there has never been involvement of the families. The involvement of families in negotiating ilobolo (bride wealth) is a pre-requisite for legitimate relationships, particularly marriage. Multiple concurrent sexual partnerships typically exist in ukujola relationships, and unprotected sex is common. There is a need for a national dialogue on ilobolo in the context of HIV and AIDS.