Abstract The nature of the transition to agriculture has been widely debated, particularly in the context of north-western Europe, where stable carbon and nitrogen isotope data have been argued to indicate a rapid, sharp shift in diet. However, other lines of evidence sometimes suggest a less complete break. This chapter provides a broad overview of this debate, drawing on the large amount of isotope data now available that permits wider regional considerations of trends in coastal and inland contexts across Europe. A clear pattern emerges, with significant differences between Mesolithic and Neolithic isotopic composition, and, by inference, diets. There are a number of notable exceptions—at the individual, site, and regional levels. Some of these can be explained simply through terminology (i.e. ‘Neolithic’ being defined regionally through technology rather than subsistence), while others appear to relate to specific local environmental conditions placing foraging and farming on a more equal footing.