Modern architects in the inter-war period were enthused by the potential of science and technology to inform their work. The educational dimension of this changing mindset was first recognised and explored at the Bauhaus in Germany, the experiments of which were to inspire the teaching of architecture in schools across Europe and the United States, particularly after the end of the second world war. In the United Kingdom, the quest for a more science-based approach to architectural education had an equally important source in the work of the government’s Building Research Station (BRS). From the early 1930s, the BRS initiated steps to familiarise architectural students with its methodologies, and in the postwar years such concerns were channelled into a comprehensive pedagogical reform agenda that culminated in the landmark Oxford Conference on Architectural Education of 1958. This article argues that it was William Allen (1914–98), rather than better-known figures such as Leslie Martin and Richard Llewelyn-Davies, who was the driving force behind this agenda. As chief architect to the BRS, Allen took up a pivotal position at the intersection of building science and professional practice. The article shows how, over the course of two decades, Allen used the institutional machinery of both the BRS and the Royal Institute of British Architects to inject a scientific outlook into the training of architects. His success in doing so positions Allen as a major figure in British post-war architecture, even though his own attempt to implement his vision as principal of the Architectural Association (1961–65) ended in failure.