The scholars consulted agree that the surname Lamberti — along with its variants Lambertini, Lamperti, and Lamberto — derives from the Germanic given name Lambert or Lampert, with the older form Lamperto. It is also recorded as derived from the given name Lamberto.

E. De Felice distinguishes two traditions within this name. The form Lamberto belongs to the Frankish tradition, documented from the end of the 8th century but common only from the 10th, while Lamperto belongs to the Lombard tradition, attested in the Latinized forms Landepertus, Lamipertus, and Lampertus. The underlying Germanic name, reconstructible as Land(o)berht, combines the elements landa- (German Land: "territory, country") and bertha- ("shining; famous, illustrious"), yielding the possible original meaning "illustrious in his own country."

E. Rossoni provides early historical documentation for the given name. He records a king Lambertus who destroyed Milan in the year 570, and, in the 9th century, a Lambertus, duke of Spoleto, mentioned in the Annales Regni Francorum. Among notable bearers of the derived surname, Rossoni highlights Cardinal Prospero Lambertini of Bologna, who became Pope Benedict XIV (1675–1758).

On geographical distribution, De Felice notes that Lamperti predominates in Lombardy, while Lambertini shows high frequency in Emilia-Romagna. Rossoni adds greater detail: Lamberti extends across northern and central-western Italy; Lambertini is typical of Emilia-Romagna, with concentrations in the Bologna and Ferrara areas and possible further clusters in the Genoa and Novara areas; Lamperti is clearly Lombard in character, with a presence in the Milan, Varese, and Como areas; and Lamberto, very infrequent, appears in the area between Messina and Reggio Calabria, and perhaps also in the Turin area.