E. Rossoni identifies it as a surname of possible Valtellina origin. He notes that Peita originates in the Tirano area and probably derives from local toponymy, since in that area there is a locality called Peita. He adds that it is also possible that the Peita of Tirano come from Poschiavo, in which case it could be an Italianization of the German surname Peiter. He further mentions that Peiti could be a surname originating in the Grosio area, in the province of Sondrio.

Other authors propose instead a Germanic origin, from a word meaning "resting place," related to the German Bau ("building"), where the p instead of b would be the classic Lombard consonant shift. As an alternative, an analogy is put forward with the Ligurian Paita, which takes up a Lombard term designating a strip of cloth, an item of clothing (comparable to the Italian patta). Peiti and Baitelli are recorded as similar surnames.