Cognitive impairment is a prevalent and debilitating symptom of multiple sclerosis (MS) but is not routinely addressed in clinical care. The Brief Cognitive Assessment for Multiple Sclerosis (BICAMS) was developed in 2012 to screen and monitor MS patients’ cognition. This systematic review and meta-analysis aimed to identify, synthesise, and critically appraise current BICAMS’ international validations. The literature search was conducted using PubMed, PsycINFO and Web of Science electronic databases in August 2022. Quantitative, peer-reviewed adult studies, which followed the BICAMS international validation protocol and were published in English, were included. The search identified a total of 203 studies, of which 26 were eligible for inclusion. These reported a total of 2833 adults with MS and 2382 healthy controls (HC). The meta-analysis showed that BICAMS identified impaired cognitive functioning in adults with MS compared to HC for all three subtests: information processing speed (g = 0.854, 95% CI = 0.765, 0.944, p < 0.001), immediate verbal recall (g = 0.566, 95% CI = 0.459, 0.673, p < 0.001) and immediate visual recall (g = 0.566, 95% CI = 0.487, 0.645, p < 0.001). Recruitment sites and strategies limit the generalisability of results. BICAMS is a valid and feasible international MS cognitive assessment.