Thomas Barnes (1785 - May 7, 1841) was a British journalist.

He was educated at Christ's Hospital and Pembroke College, Cambridge. He came to London and soon joined the famous literary circle of which Hunt, Charles Lamb and William Hazlitt were prominent members. Upon the retirement of Dr John Stoddart in 1817 he was appointed editor of The Times, a position which he held until his death, when he was succeeded by John Delane. Lord Lyndhurst gave expression to a very widely-held opinion when he described him as "the most powerful man in the country."