Thomas Lynn (1774–1847) was an English naval officer and writer on astronomy.
He was born 2 January 1774 at Woodbridge, Suffolk, where his father was a medical practitioner.
At the age of 11 he entered the naval service of the East India Company.
On leaving it with the rank of commander many years later, he was appointed examiner in nautical astronomy to the company's officers.
He kept a naval academy at 148 Leadenhall Street, London, and died at Dover on 2 May 1847, aged 73.