The transformation in Catholic schooling after the Education (Scotland) Act, 1918, is widely recognised. But research on the building of Catholic schools, beginning with the early decades of the nineteenth century, has not yet been done to a level that can support the claim that the ‘greatest impact’ on building was the transfer of voluntary Catholic primaries to the education authorities. By contrast with the history of Catholic education, there has been no thematic study of Scotland's historic school architecture. The aim here is to address that gap, and provide a foundation for further study, by tracing the early development of Catholic school buildings down to the Education (Scotland) Act, 1872. Educational historians have maintained the narrative that, before 1872, many school buildings were ‘little more than hovels’, and the date of 1918 has been identified as the watershed for improvement. That view is challenged.