Older single women in Australia are increasingly experiencing homelessness. Age and gender seem inherently related to single older women’s housing crises, but no attempt has been made to account for the causes of their homelessness through an intersectional lens. This article develops a complex and contingent causal explanation of the structures and mechanisms implicated in growing homelessness for this group. We demonstrate an original use of critical realist-informed intersectional analysis which is characterized by stratified social ontology and emergence. We theoretically (...) reframe existing literature to demonstrate how the intersectional causal powers of gender and age (‘gender*age’) discrimination and conventional life course experiences intersect to generate financial precarity for older women. Our causal model explains how economic insecurity, structural and individual contexts, and crisis events interact, challenging older women’s housing security and precipitating first-time homelessness later in life. (shrink)