This paper contemplates the evolution of Pigou's stance towards the Keynesian Revolution. Preliminarily, a brief contrast between his and Keynes's approach to the problem of unemployment is made. After that, Pigou's first reactions to The General Theory are presented, along with the rejoinder from the Keynesian camp. In the sequence, the emergence of the "Pigou effect" in the context of the classical stationary state long run equilibrium is reconstituted, as well as the body of criticism to such mechanism formulated by many economists at that time. In the end, Pigou's last assessment of Keynes's contribution to economic theory is retrieved, comparing it to his initial impressions on the advance of Keynesianism in the academic world.