John I of Brienne, Count of Eu

John I of Brienne (c. 1250–1294) was Count of Eu in Normandy. The eldest son of Alphonse of Brienne and Marie of Lusignan, the heiress of Eu, he inherited the county on his mother's death in 1260 and ruled under his father's tutelage until 1270. Through his father he was a grandson of John of Brienne, king of Jerusalem.

He married Beatrice, daughter of Guy III, Count of Saint-Pol, who bore him his heir John II and a daughter Mahaut. He died in 1294.