The surname Oldani is of Lombard origin and can be explained both by the toponymic and by the anthroponymic route. In this sense, E. De Felice links it with the ethnic derived from the place name Olda (in the Bergamo area), while E. Rossoni broadens this interpretation by including other possible origins related to localities such as Olda di Vedeseta or with the medieval name Oldanus, of probable Lombard root.

E. Rossoni further supplies historical documentation that confirms the early presence of the name in medieval Italy, which reinforces its subsequent fixing as a surname. In this way, the surname may have arisen both to indicate geographical provenance and from a personal name, in line with the usual processes in the formation of Italian surnames.