Catherine Betty Abigail Behrens (24 April 1904 – 1989), known as Betty Behrens and published as C. B. A. Behrens, was a British historian and academic. Her early interests included Henry VIII, Charles II, and the early modern period of English history, with her later research focused on the "Ancien Régime" (the Kingdom of France from the Middle Ages to the French Revolution). She was elected a Fellow of Newnham College, Cambridge in 1935, and moved to become a Fellow of Clare Hall, Cambridge after the publication of "The Ancien Régime" (1967). She "achieved an international reputation" with "The Ancien Régime", with reviews describing it as "remarkable and absorbing" and "a lively, thought-provoking essay in historical revision".