The surname Ruggero and its derivatives (such as Ruggeri, Roggeri, Geri, Geretti, Gerussi, Giretti and Tuscan forms in -rini) have their origin in the Germanic given name Ruggero, introduced into Italy mainly by the Normans. This name derives from the Old Frankish Hrodger (or Hrodgar, Hrodegar), composed of the roots hrod ("glory, fame") and gar ("spear, javelin"), with the meaning of "famous for his spear."

In medieval documentation it also appears in Latinized forms such as Rodegarius or Rodigerius. Its diffusion was reinforced by the Christian tradition, in particular by a 7th-century saint venerated in Barletta, celebrated on 15 October. From this personal name the present-day surnames and their multiple regional variants derive directly.