Hepatitis B virus (HBV) is a major global health challenge. Emerging evidence suggests that poor knowledge and stigma are impacting HBV control efforts in sub-Saharan Africa (SSA), however their role is not well understood. We conducted a cross-sectional study of adults aged ≥ 18 years in a community and pharmacy setting in Freetown, Sierra Leone. A structured questionnaire was used to assess knowledge, stigmatizing attitudes, and health-seeking behaviors regarding HBV. Logistic regression was used to identify predictors of HBV knowledge and related stigma. A total of 306 adult participants were enrolled (50.7% male, 7.5% HBV positive and 11.7% vaccinated). Overall, 52.2% had comprehensive HBV knowledge and 49.3% expressed a stigmatizing attitude towards people with HBV. Notwithstanding, 72.2% stated they would receive the HBV vaccine if offered, 80.4% would take anti-HBV medication and 78.8% would be willing to attend clinic regularly. Comprehensive HBV knowledge was associated with HBV positive status (aOR 4.41; p = 0.029) and being vaccinated against HBV (aOR 3.30; p = 0.034). HBV-related stigma was associated with secondary or higher level of education (aOR 2.36; p < 0.001), good HBV knowledge (aOR 2.05; p = 0.006) and pharmacy setting (aOR 1.74, p = 0.037). These findings suggest that education and stigma reduction may benefit HBV elimination efforts in SSA.