Gisulf I (also Gisulph, Gisolf, Gisulfo, Gisolfo, Gisulphus, or Gisulfus) (May 930 – November or December 977) is the eldest son of his father, Guaimar II, and his second wife Gaitelgrima.

He is associated with his father as prince of Salerno in 943 and he succeeds him on his death in 952.

He takes to using the title Langobardorum gentis princeps: "prince of the people of the Lombards."

He is originally under the regency of his mother and Prisco (Priscus), treasurer (comes tesaurarium) and count of the palace (magister palatii).