Environmental science is an interdisciplinary field. However, many definitions or descriptions of this field do not explicitly include the social sciences even though environmental and social challenges are deeply interlinked. The key aim of this project was to co-produce tailored resources and practical approaches to bridging disciplines and sectors. The toolkit provides a practical framework and supporting information for collaborative working across disciplines and sectors within the environmental sciences. It is designed to be flexible rather than prescriptive, so that it is applicable for projects spanning research, policy, and practice. The toolkit is structured around the BRIDGES Framework co-developed for this project.