The surname Bertasi and its variants —such as Bertasini and Bertaso— have an anthroponymic origin linked to Germanic names spread in medieval Italy. According to E. Rossoni, they derive —directly or through diminutive forms— from the Latinisation of the Germanic name Berhtwald, composed of berhta ("light, bright") and wald ("government"), meaning "the one who governs in an enlightened way" or "brilliant ruler". This type of name reflects the Germanic tradition of combining elements with symbolic value and desired qualities.

From the geographical point of view, E. Rossoni notes that Bertasi presents clusters in the Milan area, on the Brescia–Mantua–Verona axis and between Rovigo and Ferrara, while Bertasini and Bertaso are specific to the Verona area. This distribution shows a strong implantation in northern Italy, especially in regions with historical Lombard influence.

For his part, F. De Laurentiis offers a more synthetic interpretation, considering them derived from Bèrti, which integrates them within the broad family of surnames originating in the name Berto. Taken together, both interpretations agree in pointing to a common Germanic origin, with a regional evolution that gave rise to various local variants.