Recent wildfires burning throughout Australia highlight the vulnerability of settlements located in wildland urban interface (WUI) areas. Spatial planning has a critical role in operationalising wildfire risk reduction considerations in a territorial manner across the WUI. Accordingly, more integrated approaches to wildfire management and spatial planning are necessary. However, there is limited literature examining the historical interactions between wildfire and spatial planning policy sectors and how institutions and policy instruments adapt over time to integrate mutually dependent considerations. To address this gap, this research examines how Australian spatial planning institutions and instruments evolved since European settlement to incorporate wildfire considerations, through a qualitative comparative case study approach of two Australian states. Based on the findings of the case study comparison, this paper presents a conceptual framework of the pathways towards increased policy integration of spatial planning and wildfire risk reduction that consists of six phases. It is argued that the path to greater policy integration is grounded on the development of common knowledge, a cross-disciplinary understanding, and agreed policy goals between different policy sectors, that, with time, translate into new institutional arrangements and instruments that integrate the work and decision-making processes of different sectors.