BACKGROUND: In 2014, UNAIDS announced the 90-90-90 treatment targets to curb the HIV epidemic by 2020: 90% of people living with HIV know their HIV status, 90% of people who know their HIV status access treatment and 90% of people on treatment have suppressed viral loads. Monitoring and evaluation are needed to track linkage and retention throughout the continuum of care. We propose a systematic review and meta-regression to identify the different methodological approaches used to define the steps in the HIV care cascade in sub-Saharan Africa (SSA), where most people with HIV live, and to assess the proportion of participants retained at each step. METHODS: We will include cohort and cross-sectional studies published between 2004 and 2016 that report on the HIV care cascade among adults in SSA. The PubMed, Embase and CINAHL databases will be searched. Two reviewers will independently screen titles and abstracts, assess the full texts for eligibility and extract data. Disagreements will be resolved by consensus or consultation with a third reviewer. We will assess the number and proportion of individuals retained in the HIV care cascade from HIV diagnosis to linkage to care, engagement in pre-ART care, initiation of ART, retention on ART, and viral suppression. The data will be analysed using random effects meta-regression analysis. Publication bias will be assessed by funnel plots. DISCUSSION: This review will contribute to a better understanding of the HIV care cascade in SSA. It will help programs identify gaps and approaches to improve care and treatment for people living with HIV and reduce HIV transmission. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42017055863.