Housing prices in Canada have increased dramatically, giving rise to a housing affordability crisis. Young adults have been disproportionately affected by this crisis. To cope, many young adults have had to alter their living arrangements, contributing to the diversification of their living arrangements. Young adults' diverse living arrangements are the product of growing inequalities in young adults' economic prospects and access to family support. Extant work has yet to document how young adults' risk of having unaffordable housing varies according to their living arrangements. Our comparison of young adults' risk of having unaffordable housing according to their living arrangements reveals that co-residence with parents, relatives, or roommates reduces young adults' risk of having unaffordable housing. This protective effect is smaller for the foreign-born than the Canadian-born. The National Housing Strategy should allocate more resources to increase the supply of affordable housing earmarked for young adults, particularly the foreign-born who live alone or with children.