Building on efforts such as the mountain-specific chapters in the Millennium Ecosystem Assessment and IPCC AR2, there has been a recent increase in large-scale efforts to synthesize and assess knowledge about mountain systems (e.g. IPCC AR6 and SROCC, the Hindu-Kush Himalaya Assessment, IPBES, and the Canadian Mountain Assessment). This session aims to cultivate a space for critical discussion and experiential reflection on methods used in recent mountain-relevant assessment activities, with a goal of improving the saliency, credibility, and legitimacy of such efforts. The event features a routable discussion with those involved in leading major mountain-focused assessments activities. Speakers will discuss their respective experience advancing systematic approaches to synthesizing and aggregating insights from diverse socio-ecological and cultural contexts into assessment reports. They will also examine heuristics and criteria used to structure assessment findings; challenges in adequately reflecting nuances across mountain systems; and questions such as what methods have worked (or not), for whom/towards what ends, how, and why?