This chapter reviews the changing perspectives that have developed in the history of economic thought (HET) literature over the course of the second half of the twentieth century and the early twenty-first century on Arthur Cecil Pigou as a "Marshallian" scholar. The finding of this review is that the general understanding of what constitutes the term "Marshallian" economics that has evolved over this time, and, as a result, two opposing perspectives of Pigou as a Marshallian economist have arisen in the literature. The first generally emphasises continuity between Pigouvian and Marshallian economic thought, while the second generally emphasises discontinuity between them. In contrast, the discontinuity thesis emphasises Pigou's failure to develop Alfred Marshall's evolutionary conceptions of industrial development and his increasing formalisation of economic theory. A pattern in the formation of historians' perceptions (or interpretations) of Pigou is found to be related to the re-emergence and flourishing of Marshall Studies from the 1980s.