The surname Bocca and its numerous variants —such as Bocchino, Boccone, Boccaccio and compounds such as Boccanegra— have a mainly nickname-based origin. According to E. De Felice, they derive from nicknames already widespread since the 11th century, formed from the noun bócca ("mouth", or bucca in the south), and used to describe physical characteristics of the mouth or, in a figurative sense, a person's way of speaking: someone sincere, deceitful, wise or imprudent. This type of denomination reflects a common practice in the Middle Ages, where physical or character traits served as identifiers.

From the point of view of diffusion, E. De Felice notes that the surname is present throughout Italy, most frequently in Liguria, Lombardy, Tuscany, the Marche and Umbria in the forms with Bo-, while in the south the variants with Bu- predominate. He also mentions specific regional compounds, such as Boccafoglia in Emilia or Boccanegra in Liguria, the latter linked to historical figures of medieval Genoa.

For his part, E. Rossoni provides a possible alternative interpretation, proposing that in some cases the surname could derive from place names related to geographical features, such as river mouths (bocca d'Adda and similar). He also places clusters of the surname in the Italian northwest, especially in areas such as Pavia, Alessandria and Turin.

Taken together, the interpretations agree in pointing to a predominantly nickname-based origin, with possible toponymic derivations in some cases, and a wide diffusion that gave rise to numerous regional variants.