Sir John Eric Sidney Thompson, KBE (31 December 1898 – 9 September 1975) was a leading English Mesoamerican archaeologist, ethnohistorian, and epigrapher. While working in the United States, he dominated Maya studies and particularly the study of the Maya script until well into the sixties of the 20th century.
Thompson was born on 31 December 1898 to father George Thompson, a distinguished surgeon and fellow of the Royal College of Surgeons of England. Thompson was raised in the family home on Harley Street in London. At the age of 14 he was sent to Winchester College to receive an independent education.
In 1915, at the beginning of World War I, Thompson used the assumed name Neil Winslow to join the British Army while underage. A year into service he was wounded and sent home to recover, first in Huddersfield then Seaford. He continued to serve in the Coldstream Guards until the end of the war, ending his service at the rank of officer.
After the war Thompson left for Argentina to work as a gaucho on a family cattle farm. When he returned to England in the early 1920s Thompson published his first article on his experience in Argentina, titled A Cowboy's Experience: Cattle Branding in the Argentine in the Southwark Diocesan Gazette.
Thompson first considered a medical or political career however he later decided to study anthropology at the Fitzwilliam House at Cambridge University under A.C. Haddon. With the completion of his degree in 1925, Thompson wrote to Sylvanus G Morley, the head of the Carnegie Institution's project at Chichen Itza, to ask for a job, inquiring about a field position. Morley accepted Thompson, most likely due to the fact that Thompson had previously taught himself to read Maya hieroglyphic dates, an accomplishment that was highly valued by Morley who also had a passion for Maya hieroglyphics.