This surname is held to be of anthroponymic origin, derived from a personal name of Germanic root. E. Rossoni specifies that the etymon is the medieval Latin name Loterius or Lotterius, of which documentary evidence exists in a Pisan deed of 1108 and in another of 1179 from Brescia. The origin is linked to the Germanic name Chlothar, with the meaning "renowned warrior".

Rossoni notes that the surname has a predominantly Lombard distribution, with a specific area in Treviglio, in the province of Bergamo, and significant presences also in Milan and in the Cremona area. He likewise records the variants Lotterio, typical of the Milan area —especially of Legnano and Milan— and Lottero, proper to the strip covering the Turin, Asti and Alessandria areas, with the greatest concentration in that of Genoa. The surname is held to have a scattered presence in the Gera d'Adda area, in Lombardy.