For many Indigenous communities who live in mountain regions around the globe, the histories of mountain park development have often facilitated dispossession from ancestral territories. Diverse Indigenous communities share similar experiences, where park interests have conflicted with Indigenous lands. However, colonial practices of park management are consistently being rethought. Canada and Aotearoa/New Zealand are examples where new designations of parks are now emerging to support management practices that assert Indigenous knowledge and land rights. Guided by Indigenous methodologies and supported by secondary literature, the analysis of policy documents, and community-based research with Indigenous communities in Canada and Aotearoa/New Zealand, this article highlights grassroots Indigenous-led park management practices that move beyond colonial frameworks. This research indicates the potential of protected areas to strengthen the livelihoods of Indigenous Peoples and mountain ecosystems by demonstrating how colonial histories can be reconciled and conservation policies integrated to support the sustainable development of mountain regions.