Mr. Manwaring is a character mentioned in Lady Susan. He is married to Mrs. Manwaring, and lives with his sister, Maria Manwaring. He often writes to Lady Susan Vernon complaining about his wife and sister. Mrs. Johnson encourages Lady Susan to have an affair with Manwaring. Lady Susan's flirtations with him have made his wife very jealous and wretched, according to Reginald De Courcy.