The brush-tailed rock-wallaby (Petrogale penicillata) is listed as vulnerable on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Parasitic diseases have been proposed as possible contributing factors to the decline of the species, but very little is known about the effects of parasites on this host. This study determined the antibody prevalence of the protist Toxoplasma gondii in a wild brush-tailed rock-wallaby population from three neighboring colonies in southeast Queensland, Australia. Fecal egg and oocyst count, tick count, severity of skin rash, and presence of lice and microfilariae were also monitored during four or five trapping periods over 1 yr. Antibodies against T. gondii were detected in 5% of animals (3/64). Fecal egg and oocyst counts were highly variable, but fecal egg counts were lower in subadult animals relative to adults. Neither fecal egg count nor oocyst count was associated with variation in blood variables or condition index, but a negative association between fecal egg count and oocyst count was observed. Microfilariae (Breinlia spelaea), lice (Heterodoxus octoseriatus), and skin lesions were seen more frequently during the November trapping period. A mite, Thadeua sp., was more likely to be detected in these skin lesions than in skin of unaffected wallabies. Tick (Ixodes holocyclus and Haemaphysalis bancrofti) counts also varied between trapping periods and were lowest in the April/May trapping period. This study provides the most detailed account to date of parasite burdens in a vulnerable macropodid, but no clear evidence emerged linking parasites to adverse impact on the host.