The authors agree that the surname is related to the function of guard or sentinel, although they differ on its geographical and etymological origin.

E. Rossoni notes that the surname could derive from the Lombard —and also Spanish— word guaita, meaning "guard" or "sentinel", and considers a Lombard filiation more likely, given the area of origin. He places its main cluster in the Mantua area, though he also documents a prominent family in the Como area, near Menaggio. The variant Guaitani, for its part, would appear to be typical of the area between Milan and Bergamo.

V. Blunda presents a different perspective: he considers the surname to be of Sicilian origin and links it to the dialect term gaitùni, which designated the shift of coastal watch or maritime guard duty. This term is associated with the system of towers and watchtowers raised between the 16th and 18th centuries to sight North African corsair ships. According to Blunda, the surname may have originated in the trade of the lookout or coastal watchman charged with that duty.