The authors agree that the surname derives from a form related to the month of March. B. Zuanella notes that the oldest documented forms are Marzulin and Marzulino, recorded in the parish of San Pietro al Natisone from at least the 17th century, and that the surname probably arrived from Friuli. According to Zuanella, Marzulin is the diminutive of the Friulian adjective marzul ("of March"), a term formerly applied to certain cereals sown in spring, to animals born in March and to a very early mushroom (Hygrophorus marzuolus). In a similar way the anthroponyms Marzola and Marzolino would have arisen, originally used to designate children born in March or in spring.

E. Rossoni specifies that the surname would derive from the medieval name Marzulinus or Marzolino, given to children born in March, and documents a mention of 1456 at Tarvisio, in the Udine area. Rossoni places the surname mainly in Friuli, with a lesser presence in the Piacenza area —at Alseno and in the city itself— and in the Parma area, besides a more important core in Rome. The variant Marzolino, extremely rare, appears scattered throughout Italy.