Leopold IV, Prince of Lippe (30 May 1871 – 30 December 1949) was the final sovereign of the Principality of Lippe in northwestern Germany from 1905 until his abdication in 1918. Prior to succeeding to the throne, he had been governing the state since 1904 as regent. He was the first and only ruler of Lippe of the Lippe-Biesterfeld branch.