Scholars agree that this surname derives from the Latin personal name Rosa. F. Miranda specifies that this is the most widespread of the floral names and that, etymologically, it comes from the Greek rhódon (ῥόδον), a term referring to the rose flower, regarded as a symbol of beauty, royalty, youth and love. G. P. Holmes adds that the surname became especially popular from the Christian Middle Ages onwards, driven by devotion to Saint Rose.

E. Rossoni notes that La Rosa is a surname typical of Sicily and of the Calabrian area close to the Strait of Messina. Miranda broadens this picture and stresses that, although the main core is Sicilian, the surname is found across almost every region of Italy, with a presence in Lombardy, Lazio, Calabria, Piedmont, Liguria, Tuscany, Emilia-Romagna, Veneto, Campania and Apulia. In Sicily it appears in every province, with a particular concentration in Catania, Messina, Palermo and Syracuse. It is also recorded as especially typical of the communes of Termini Imerese, in the province of Palermo, and Aragona, in the province of Agrigento.

The variant Larosa, written as a single word, is much rarer; Rossoni records it in two specific, localized areas: one in the area of Reggio Calabria and one in the area of Bari.