Hepatitis B virus (HBV) is a public health problem worldwide, and apart from infecting humans, HBV has been found in nonhuman primates. This study investigated the prevalence and phylogenetic analysis of hepatitis B virus (HBV) and hepatitis D virus (HDV) among nonhuman primates in Taiwan, an area where human HBV remains endemic. Serum samples from 286 captive nonhuman primates (i.e., 32 great apes [Pan troglodytes and Pongo pygmaeus], 42 gibbons [Hylobates sp. and Nomascus sp.], and 212 Cercopithecidae monkeys) were collected and tested for the presence of HBV- and HDV-specific serologic markers. None of the Cercopithecidae monkeys were reactive against serologic markers of HBV. In contrast, 21.9% (7/32) of great apes and 40.5% (17/42) of gibbons tested positive for at least one serologic marker of HBV. Of these, five gibbons were chronic HBV carriers, characterized by presence of HBV DNA and hepatitis B surface antigen in the serum. HBV DNA was also detected in the saliva of three of the chronic carries. None of these HBV carrier gibbons exhibited symptoms or significant change in serum clinical chemistry related to HBV infection. Phylogenetic analysis of the complete HBV genome revealed that gibbon viruses clustered with other HBV isolates of great apes and gibbons from Southeast Asia and separately from human-specific HBV. None of the HBV-infected animals were reactive against HDV. These findings indicate that HBV found in these animals is indigenous to their respective hosts and might have been introduced into Taiwan via the direct import of infected animals from Southeast Asia. To reduce the horizontal and vertical transmission of HBV in captive animals, the HBV carriers should be kept apart from uninfected animals.