Mehmed I (Ottoman Turkish: چلبی محمد‎, Mehmed I or Mehmed Çelebi) (1381, Bursa – 26 May 1421, Edirne, Ottoman Sultanate) was the Ottoman Sultan (Rûm) from 1413 to 1421. He was one of the sons of Bayezid I and Devlet Hatun. Mehmed's reign was marked by the Ottoman Interregnum, a civil war that divided the Sultanate. He managed to reunite the Sultanate before his death in 1421.

Born in Bursa in 1390 to sultan Bayezid I and one of his wives, Devlet Hatun, Mehmed was the third oldest son of Bayezid. Along with his brothers from various mothers, including Süleyman Çelebi, İsa Çelebi, Mustafa Çelebi, and Musa Çelebi, Mehmed had the title Çelebi, meaning "gentleman."

On 20 July 1402, his father Bayezid was defeated in the Battle of Ankara by the Turko-Mongol conqueror and ruler Tamerlane. The brothers (with the exception of Mustafa, who was captured and taken along with Beyazid to Samarkand) were rescued from the battlefield, Mehmed being saved by Bayezid Pasha, who took him to his hometown of Amasya. Mehmed later made Bayezid Pasha his grand vizier (1413–1421).

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