Sir Eustace Edward Twisleton-Wykeham-Fiennes, 1st Baronet, known as Sir Eustace Fiennes, was a British soldier, Liberal politician, colonial administrator and sportsman.

Baron Saye and Sele is a title in the Peerage of England held by the Twisleton-Wykeham-Fiennes family. The title dates to 1447 but it was recreated in 1603. Confusion over the details of the 15th-century title has led to conflicting order for titleholders; authorities such as Burke's Peerage and Debrett's Peerage do not agree on whether or not the 1447 creation is still extant.