Climate change is already affecting the distribution and composition of ecological communities through range shifts, population declines, and extinctions. These community changes have major implications for biodiversity, ecosystem services, agriculture, and fisheries. Accurate predictive models are needed to manage these climate-change impacts proactively. No analog communities are expected to emerge because novel climates will form and because species differ in response to climate change owing to varying abilities to disperse, adapt, and tolerate climate change. Despite the importance of biotic factors, most predictions focus on how abiotic conditions (climate, environment) drive single species' responses to climate change and generally rely on correlative distribution models. Alternatively, multi-species mechanistic models can include biotic factors, but are difficult to parameterize. How do we tackle the complexity of biotic and abiotic factors involved in predicting changes to communities during climate change? This symposium examines these issues through insights from theoretical and applied fields, identifies areas needing further research, and highlights ways to move forward in theory and practice. Speakers will discuss responses to past climate change in the fossil record, what we can learn from long-term empirical datasets, how to incorporate community ecology into predictive models, and how to connect community-based predictions with policy and management.