Through the lens of UK CATAPULT Centres this conceptual paper presents an examination of the links between open innovation, the Triple Helix model and regional innovation systems. Highlighting the importance of boundary-spanning intermediaries, the combined role of these concepts is explored in detail. A conceptual model is then proposed which shows how the Triple Helix model of innovation occurs within regional innovation systems, and how it is underpinned by open innovation principles. Finally, areas requiring further research are discussed, with a call for further emphasis on and exploration of the overlapping nature of the concepts.