IntroductionAntiretroviral therapy (ART) initiation in infants living with HIV before 12 weeks of age can reduce the risk of mortality by 75%. Point‐of‐care (POC) diagnostic testing is critical for prompt ART initiation; however, despite its availability, rates of ART initiation are still relatively low before 12 weeks of age. This systematic review describes the barriers to ART initiation in infants before 12 weeks of age, despite the availability of POC.MethodsThis systematic review used a narrative synthesis methodology. We searched PubMed and Scopus using search strategies that combined terms of multiple variants of the keywords “early infant initiation on antiretroviral therapy,” “barriers” and “sub‐Saharan Africa” (initial search 18th January 2023; final search 1st August 2023). We included qualitative, observational and mixed methods studies that reported the influences of early infant initiation on ART. We excluded studies that reported influences on other components of the Prevention of Mother to Child Transmission cascade. Using a deductive approach guided by the updated Consolidated Framework of Implementation Research, we developed descriptive codes and themes around barriers to early infant initiation on ART. We then developed recommendations for interventions for the identified barriers using the action, actor, target and time framework from the codes.ResultsOf the 266 abstracts reviewed, 52 full‐text papers were examined, of which 12 papers were included. South Africa had most papers from a single country (n = 3) and the most reported study design was retrospective (n = 6). Delays in ART initiation beyond 12 weeks in infants 0–12 months were primarily associated with health facility and maternal factors. The most prominent barriers identified were inadequate resources for POC testing (including human resources, laboratory facilities and patient follow‐up). Maternal‐related factors, such as limited male involvement and maternal perceptions of treatment and care, were also influential.DiscussionWe identified structural barriers to ART initiation at the health system, social and cultural levels. Improvements in the timely allocation of resources for POC testing operations, coupled with interventions addressing social and behavioural barriers among both mothers and healthcare providers, hold a promise for enhancing timely ART initiation in infants.ConclusionsThis paper identifies barriers and proposes strategies for timely ART initiation in infants.