Many developed countries are experiencing a housing affordability crisis. Ethnic minorities in these countries are more likely than Whites to experience housing affordability issues and may be forced to “double up” with kin. Extant studies, however, have not investigated the extent to which intergenerational co-residence reduces the risk of living in unaffordable housing. Although the prevalence of multigenerational households differs across ethnic groups, existing work also seldom assesses whether some ethnic groups benefit more from intergenerational co-residence. Using confidential microdata from the 2016 Canadian Census, we examined the association between grandparent co-residence and children’s odds of living in unaffordable housing. We also investigated whether the association between grandparent co-residence and odds of living in unaffordable housing varied by family ethnicity, maternal relationship status, and maternal income. Grandparent co-residence was associated with lower odds of living in unaffordable housing. The association between grandparent co-residence and living in unaffordable was larger for Whites than for ethnic minorities. This ethnic difference likely emerged due to differential selectivity: multigenerational co-residence is less common among Whites; thus, it selects particularly disadvantaged Whites. Our study suggests that intergenerational co-residence may be a strategy adapted by disadvantaged groups, including ethnic minorities, to reduce their housing vulnerability.