The role of species’ interactions for determining range margins has been broadly discussed in ecology with little consensus. While established hypotheses posit that interactions may be more important on the warm vs cold edge of species ranges, a growing number of empirical studies of both plant and animal taxa are showing that interactions can be important on either edge. Further missing from the discussion is the role of mutualisms or positive species interactions which also play important roles in setting range margins in some contexts including abiotically stressful range edges. Layered over this ongoing debate is the role of climate change in altering the abiotic conditions at species range margins, modifying interactions, and causing range shifts. Thus, it is critical that we take integrative approaches to understanding the role of species interactions in setting range margins. This session brings together researchers who study biotic interactions at range margins across a broad range of ecosystems to explore general patterns and specific empirical studies that bring important perspectives to the table. Specifically, talks will cover competition, predation and mutualisms in plants and animals in both terrestrial and aquatic environments.