Alexandra Marie Walsham CBE FRHistS FBA FAHA (born 4 January 1966) is an English-Australian academic historian. She specialises in early modern Britain and in the impact of the Protestant and Catholic reformations. Since 2010, she has been Professor of Modern History at the University of Cambridge and a Fellow of Trinity College, Cambridge. She is co-editor of Past & Present and Vice-President of the Royal Historical Society.