Recently the term green infrastructure has come to shape professional and scientific debate, political strategies and practical approaches concerning green space development, particularly in urban areas. Actors from all fields of spatial development and planning are referencing this as an emergent approach, which is expected to have a considerable environmental and socio-economic impact. The wide and ubiquitous use of the term in planning debates fosters an impression of agreement in its definition and meaning. Yet several theoretical studies and manifold practical observations confirm a variety of definitions and meanings of this “new” approach in the scientific, political and practical arenas, ranging from simply a buzzword to a mature approach. Clearly, this confusion in meaning has a practical relevance for planning. It seems wise, therefore, to raise awareness and deepen our understanding of the different conceptions of the term green infrastructure. This paper aims to systematically analyse and clarify the contextual, geographical and temporal origins of green infrastructure, as well as its impact on rationales, semantic content and main purposes for spatial planning. To this end, a content analysis of relevant literature has been conducted to reveal the strands which influence the current debate as well as the application of green infrastructure in planning practice. These results are used to derive key statements as a foundation for further critical reflection and conscious application of the term green infrastructure within spatial planning.