Mammalian dispersal tends to be male-biased although female-biased dispersal has also been reported in a range of taxa. Most of our knowledge on mammalian sex-biased dispersal is based on studies of eutherians and less work has been done on the direction and causes of sex-biased dispersal in marsupials. This study investigated dispersal of swamp wallabies between two habitat patches in South Gippsland, Victoria, using genetic methods. A Bayesian clustering test showed a high level of genetic exchange between the two habitat patches despite their separation by 10–17 km of cleared land, a creek and a highway. Females in the overall sample were more closely related to each other than males were to each other and females within habitat patches were more closely related than females between habitat patches whereas the converse was true for males. Bayesian inference showed that more males were migrating from the east to the west habitat patch whereas the converse was true for females and the male migration rate was higher than the female migration rate. The differential migration rate did not cause a significant difference in relatedness between patches in females but it did in males. These relatedness and migration patterns indicate that dispersal in the swamp wallaby is male-biased.