Hepatitis B virus (HBV) infection is one of the most serious and prevalent viral diseases in the world. Although several anti-HBV drugs have been used clinically, their side and adverse effects limit treatment efficacy. Therefore, it is necessary to identify novel potential anti-HBV agents. The flavonol quercetin has shown activity against some retroviruses, but its effect on HBV remains unclear. In the present study, quercetin was incubated with HepG2.2.15 cells, as well as HuH-7 cells transfected with an HBV plasmid. Quercetin was shown to significantly reduce Hepatitis B surface antigen (HBsAg) and Hepatitis B e antigen (HBeAg), secretion and HBV genomic DNA levels in both cell lines. In addition, co-incubation with lamivudine (3TC), entecavir (ETV), or adefovir (Ade) further enhanced the quercetin-induced inhibition of HBV replication. This inhibition was partially associated with decreased heat shock proteins and HBV transcription levels. The results indicate that quercetin inhibited HBV antigen secretion and genome replication in human hepatoma cell lines, which suggests that quercetin may be a potentially effective anti-HBV agent.