Gerhard I, Count of Holstein-Itzehoe

Gerhard I (1232–1290) was Count of Holstein-Itzehoe, the second son of Count Adolf IV. From 1238 he ruled jointly with his elder brother John I under the guardianship of Duke Abel of Schleswig. In 1261 the brothers divided the county, Gerhard receiving Itzehoe with Stormarn and Plön.

He won the Battle of Loh Moor in 1262 and, after John's death in 1263, governed Kiel as regent for his nephews. He died in December 1290; his sons partitioned Itzehoe into Plön, Pinneberg and Rendsburg.