Thomas Francis Dermot Pakenham, 8th Earl of Longford (born 14 August 1933), known simply as Thomas Pakenham, is an Anglo-Irish historian and arborist who has written several prize-winning books on the diverse subjects of African history, Victorian and post-Victorian British history, and trees.

His father was created a life peer in addition to his hereditary titles in order to be able to retain his seat in the upper house.

They have four children:[1] Valerie Pakenham, Countess of Longford, died on 22 January 2023 at the age of 83.

After returning to Britain, he worked on the editorial staff of the Times Educational Supplement, and later for The Sunday Telegraph and The Observer.

He now divides his time between London and County Westmeath, Ireland, where he is the Chairman of the Irish Tree Society and honorary custodian of Tullynally Castle.