"Spatial planning" is a phrase that now resonates throughout many planning systems across the globe. It is being used as a label to describe pan-national, regional, strategic and even aspects of local planning processes. Within the UK, spatial planning is being utilized alongside, or even in place of, more traditional phraseology associated with planning, such as "town and country planning". It is being used by a range of institutions of the State, professional groups and academic commentators to describe the processes of planning reform, modernization, policy integration, and strategic governance that politically are now required to make planning fit for purpose in the 21st century. The precise meaning and definition of spatial planning remains difficult to pin down, as does its origins within the UK. This paper attempts to dissect the various components of the spatial planning phrase and set out the meaning and origins of the term in the UK context. It covers re-territorialization, Europeanization and integration origins of spatial planning thinking and provides a conceptual, rather than practical, debate on the anatomy of spatial planning, situated within ongoing processes of institutional transformation, through the lens of governance and distinctiveness in state policy development.