The Naesmyth Baronetcy, of Posso in the County of Peebles, was a title in the Baronetage of Nova Scotia. It was created on 31 July 1706 for James Naesmyth. The second Baronet sat as Member of Parliament for Peeblesshire and was an amateur botanist and Fellow of the Royal Society. The title became extinct on the death of the eighth Baronet in 1928.
The name "Naesmyth of Posso" was taken as a surname by an Anglican clergyman, George Cresswell Naesmyth Webb (1895-fl.1977), who served as Sequestrator of Southwick with Boarhunt in Hampshire between 1944-75. His connection with the family of Naesmyth is unclear.