Pepin I or Pepin I of Aquitaine (French: Pépin; 797 – 13 December 838) was King of Aquitaine and Duke of Maine.
Pepin was the second son of Emperor Louis the Pious and his first wife, Ermengarde of Hesbaye. When his father assigned to each of his sons a kingdom (within the Empire) in August 817, he received Aquitaine, which had been Louis's own subkingdom during his father Charlemagne's reign. Around this time, the only coinage issue bearing Pepin's name was struck, likely at Louis's behest.