This study investigates gender differences in the associations between social characteristics and men's and women's reports of which spouse initiated marital separation. Using retrospective data on 9,147 first marriages from the Household Income and Labor Dynamics in Australia survey (2001), we find that some social characteristics differentiated between separations initiated by wives compared to husbands, but few differences were statistically significant. The main gender difference is that wives are more inclined than husbands to initiate separation on the basis of their husbands' as well as their own social characteristics. Our findings indicate that taking account of which spouse initiates separation is important for improving our understanding of gender differences in the processes of marriage breakdown, but more research is required.