The ecosystem approach (EA) has been widely adopted as an overarching principle of marine spatial planning (MSP). However, this concept is variously understood and not necessarily translated into practice to MSP participants’ satisfaction. Differences focus around deterministic and relativistic views of the ecosystem and the subsequent role of MSP in prioritising ecological imperatives or balancing competing interests. These issues are explored here through an empirical study of the MSP process in Germany, where the EA has been given policy importance. Responses from participants indicate widespread support for the EA, though this is generally interpreted along the lines of institutional interest, with different understandings regarding the integration of socio-economic activities into the marine environment. Results support the assumption that varying meanings about the EA are being constructed through practice, and echo a wider shift in EA thinking from scientific absolutism to changing sets of guiding principles. The findings lead to the suggestion that more open and accommodating exchange between actors on their perspectives about the EA within MSP processes can lead to a productive development and application of the concept, in line with related notions of collaborative engagement.