Approximately 13% of people living with HIV in the UK are unaware of their infection. New diagnoses among people ≥50 years is increasing. Unique factors may be associated with testing in this group. This systematic review aims to identify patient and clinician-related barriers/facilitators to HIV testing in people aged ≥50 years. A systematic electronic search was conducted. Papers were assessed for eligibility and data from eligible studies were extracted. Barriers/facilitators were grouped, and the number of times they were reported was noted. Because of considerable heterogeneity, a narrative approach has been undertaken to synthesise data. In total, 17 studies were included. Main barriers to testing were low perceived risk and clinicians’ preconceptions about older people. Main facilitators were regular use of healthcare services or being offered/encouraged to test by a healthcare provider. Although being encouraged to test was a common facilitator, clinicians’ preconceptions about older people was the biggest barrier. This shows a divide between clinicians’ preconceptions and patients’ expectations, which may impact on testing rates. This review is an important first step in identifying potential barriers/facilitators for further study or to be addressed in the design of future interventions.