E. Rossoni notes that this surname derives, directly or through diminutives, from the medieval name Mariotus or Mariottus, modifications of the Latin name Marius, documented in a text of 1400 and on a Pesaro tombstone of 1532. Mariotti is found throughout central and northern Italy. Mariottini is proper to Tuscany, Umbria, the Viterbo area and the Rome area. Mariottino is almost non-existent and could be due to a transcription error for the previous form or to a form of southern Italy. Mariotto is specifically proper to Veneto.

F. De Laurentiis contributes that the base name, Mario, is of Italic origin, probably linked to the Etruscan word maru, with the sense of "man" and later the name of an office, transmitted from the Etruscans to the Umbrians and from these to the Romans, who derived from it their Mariu(m). He further notes that in some cases the surname could reflect the place name Mariotto rather than the personal name.