Clinical guidelines are used to translate research findings into evidence-based clinical practice but are frequently not comprehensively adopted by health workers (HWs). HIV and infant feeding guidelines were revised by the World Health Organization to align feeding advice for HIV-exposed and unexposed infants, and these were adopted in South Africa in 2017. We describe an innovative, team-based, mentoring programme developed to update HWs on these guidelines. The intervention was underpinned by strong theoretical frameworks and aimed to improve HWs' attitudes, knowledge, confidence, and skills about breastfeeding in the context of HIV.10.1111/mcn.1292