Friedrich I of Württemberg, or Frederick I of Württemberg (November 6, 1754 - October 30, 1816) became Duke of Württemberg in 1797 on the death of his father: he assumed the title of Elector in 1802, and the title of King in 1806.

He was obese: behind his back he was known as "The Great Belly-Gerent", and Napoleon Bonaparte later remarked that God had created the Prince to demonstrate the utmost extent to which the human skin could be stretched without bursting.