Ricco, of an auspicious and anthroponymic origin, derives from the medieval adjective ricco ("prosperous, favoured, powerful"), very diffused as a personal name in medieval Italy. In many cases it is also linked to hypocoristics of Germanic names ending in -rico (such as Enrico, Federico, Oderico), which explains its wide geographic dispersion.

Multiple independent historical foci are noted, with a presence documented in the north (Liguria, Piedmont, Friuli–Carnia), the south (Calabria) and Sardinia, where the surname was integrated early into the local onomastics. For this reason, it does not point back to a single line, but to different families that fixed the surname from the same symbolic value: prosperity, strength or prestige.

Variants of the surname are also recorded: Ricchi, diffused mainly in Tuscany and areas of the centre-north, as a patronymic or family plural form ("the Ricco family"), sometimes linked to abbreviated Germanic names such as Rikko; Ricca, present in Liguria, Piedmont and Sicily, as a feminine or dialect morphological variant of Ricco; Ricu and Riccu, local phonetic adaptations in Sardinia and Sicily; and Ricchiardi and Riccardi, very diffused throughout the country, derived from the Germanic name Ric(h)ard ("potent, strong"), which share the semantic root rik- ("power, wealth").

E. De Felice agrees that the surname was normally formed from the auspicious name Ricco (feminine Ricca), derived from ricco, documented in Tuscany from the 11th century. He adds that, in some cases —especially for Ricco, Ricchi and Ricchieri—, it may also represent the Germanic hypocoristic Rikko, an abbreviation of names compounded with -rico or Rica- (from rikia-, "powerful; lord"), such as Enrico, Federico or Oderico, or a variant of the aphaeretic hypocoristic Rico of those same names.

E. Rossoni identifies it as typical of the area comprising the Parma, Reggio Emilia, Modena and Mantua areas, on the border with Emilia. He proposes that it may derive from the initial reduction of names such as Federico, Alarico or Ulderico, or from the initial part of names such as Riccobono or Riccomanno.

V. Blunda, for the Sicilian variant, derives it from the Germanic personal name Rikhi, linked to the root ric ("power, domain") in its simple form. This root had in ancient Germanic the main sense of "power" or "domain," preserved in the modern German Reich, while the semantic shift towards the patrimonial sense of "rich" (possessor of goods) was a secondary evolution of the term in the medieval Romance languages.

Blunda clarifies that the popular interpretation that associates the surname with the Italian adjective ricco ("one who has much wealth") is a partial cross-etymology: both terms share a Germanic origin, but with divergent semantic developments.