Hepatitis B virus (HBV) infection is a major public health problem in Sierra Leone, yet reliable estimates of cases are lacking. This study aimed to provide an estimate of the national prevalence of chronic HBV infection in the general population and select groups in Sierra Leone. We used the electronic databases PubMed/MEDLINE, Embase, Scopus, ScienceDirect, Web of Science, Google Scholar, and African Journals Online to systematically review articles reporting hepatitis B infection surface antigen seroprevalence estimates in Sierra Leone during 1997-2022. We estimated pooled HBV seroprevalence rates and assessed potential sources of heterogeneity. Of 546 publications screened, 22 studies with a total sample size of 107,186 people were included in the systematic review and meta-analysis. The pooled prevalence of chronic HBV infection was 13.0% (95% CI, 10.0-16.0) (I2 = 99%; Pheterogeneity < 0.01). During the study period, the HBV prevalence rates were as follows: 17.9% (95% CI, 6.7-39.8) before 2015, 13.3% (95% CI, 10.4-16.9) during 2015-2019, and 10.7% (95% CI, 7.5-14.9) during 2020-2022. The use of the 2020-2022 HBV prevalence estimates corresponded to 870,000 cases of chronic HBV infection (uncertainty interval, 610,000-1,213,000), or approximately one in nine people. The highest HBV seroprevalence estimates were among adolescents aged 10-17 years (17.0%; 95% CI, 8.8-30.5), Ebola survivors (36.8%; 95% CI, 26.2-48.8), people living with HIV (15.9%; 95% CI, 10.6-23.0), and those in the Northern Province (19.0%; 95% CI, 6.4-44.7) and Southern Province (19.7%; 95% CI, 10.9-32.8) regions. These findings may help inform national HBV program implementation in Sierra Leone.