A renaissance in organismal biology has been sparked by recent conceptual, theoretical, methodological, and computational advances in the life sciences, along with an unprecedented interdisciplinary integration with Mathematics, Engineering, and the physical sciences. Despite a decades-long trend toward reductionist approaches to biological problems, it is increasingly recognized that whole organisms play a central role in organizing and interpreting information from across the biological spectrum. Organisms represent the nexus where sub- and supra-organismal processes meet, and it is the performance of organisms within the environment that provides the material for natural selection. Here, we identify five "grand challenges" for future research in organismal biology. It is intended that these challenges will spark further discussion in the broader community and identify future research priorities, opportunities, and directions, which will ultimately help to guide the allocation of support for and training in organismal biology.