Working across knowledge-based research programmes, rather than institutional structures, should be central to interdisciplinary research. In this paper, a novel framework is proposed to facilitate interdisciplinary research, with the goals of promoting communication, understanding and collaborative work. Three core elements need to be addressed to improve interdisciplinary research: the types (forms and functions) of theories, the underlying philosophies of knowledge and the combination of research styles; these three elements combine to form the research programme. Case studies from sustainability science and environmental security illustrate the application of this research programme-based framework. This framework may be helpful in overcoming often oversimplified distinctions, such as qualitative/quantitative, deductive/inductive, normative/descriptive, subjective/objective and theory/practice. Applying this conceptual framework to interdisciplinary research should foster theoretical advances, more effective communication and better problem-solving in increasingly interdisciplinary environmental fields.