Andres Vazquez de Prada y Vallejo (19 December 1924 in Valladolid – 27 August 2005 in Madrid) was a Spanish historian, lawyer, professor, diplomat and writer.
In 1947, his doctoral thesis, General Theory of De Facto Governments, obtained the prize for outstanding work at the University of Madrid.
He has published several studies on important figures in the English Catholic Church, including The dream of an old man (1954) on John Henry Newman.
He played an active role in the start and growth of Opus Dei's apostolic work in the United Kingdom.
From 1977 on he devoted himself full-time to researching the life of St. Josemaria Escriva de Balaguer which resulted in his three-volume biography of the founder of Opus Dei.