On 27 October 1930 Caetano married Maria Teresa Teixeira de Queirós de Barros (23 July 1906 – 14 January 1971), the sister of antifascist politician Henrique de Barros, 1st and only President of the Constituent Assembly of Portugal, daughter of writer João de Barros and wife Raquel Teixeira de Queirós and paternal granddaughter of the 1st Viscount of Marinha Grande, and had four children: