John Wenlock, 1st Baron Wenlock (c.1400/04 – 4 May 1471) was an English politician, diplomat, soldier and courtier. He fought on the sides of both the Yorkists and the Lancastrians in the Wars of the Roses. He has been called "the prince of turncoats", although some historians suggest the label may not be fair as this behavior was commonplace during the Wars of the Roses. Others contend that even when Wenlock was not actually changing sides, he was engaged in "fence sitting par excellence."

Although Wenlock is often remembered for his military exploits (he fought in six of the major battles of the Wars of the Roses, as well as the sieges of the Tower of London and Dunstanburgh Castle), most of his public service was in the diplomatic field, and contemporary accounts record him as being regarded as "very clever".