E. Rossoni proposes that Gambarini would derive from the place name Gambara, in the Brescia area. He also notes the existence of the medieval name Gambarus, documented in the Codice Diplomatico della Lombardia Medioevale in deeds of 1166 and 1192, which mention respectively Sozo Gambarus, notarius sacri palatii and a consul Mediolani with that name. A trace of its transformation into a surname appears in the Angevin period with the lawyer Dullio Gamberini of Alessandria, professor of Law. Rossoni indicates that Gambarini is peculiar to the Bergamo, Milan and Brescia areas.

From another perspective, it is considered that the surname could be linked to Gambara, name of the mythical mother of the Lombards, or to its masculine equivalent Gambaro, with the possible meaning of "witness, counsellor, companion", in relation to the Lombard *gamahal. The Old High German gambar, with the sense of "bold", is also noted as the more probable etymon. The surname has documented presence in the Valcalepio area.

F. De Laurentiis proposes a derivation from the term "leg", without developing further etymological grounding.