The authors agree that this surname derives from the given name Luca, which continues the Latin Lucas or Luca, an adaptation of the Greek Loukas. A. Bongioanni notes that, according to Fumagalli, the name would be no more than a variant of the Latin Lucius and Lucia, derived from lux, with the meaning "luminous". F. Miranda broadens this etymology and proposes that Loukas could in turn derive from the Greek Leucos ("white, luminous") or from Lyke ("dawn, brightness"), and that it might also be traced back to the Latin lucere ("to dawn, to be born with the light"). G. P. Holmes adds the possibility that the origin is lucanus, that is, "native of Lucania", a hypothesis Miranda also records when mentioning the Greek lycanòs.

The spread of the name —and therefore of the surname— is due to the cult of Saint Luke the Evangelist, author of the third Gospel and of the Acts of the Apostles. Bongioanni notes that the patronymic De Luca is very frequent in southern Italy, that the form with double c, Lucca, predominates in the north, and that Lucantoni is proper to central Italy. E. Rossoni specifies that the accented variant Lucà is typically Calabrian, with a presence in Petilia Policastro and Cirò Marina, in the province of Crotone, and in Gioiosa Ionica, Marina di Gioiosa Ionica and Bianco, in the Reggio Calabria area; this form would derive directly from Loukas, the Greek form of the evangelist's name.

On the geographical distribution of the surname Luca, Rossoni notes that it is very widespread in Sicily, especially in the Messina, Catania and Palermo areas, with a presence also in the Lecce area, in the region of the Marche and in the Udine and Trieste areas. Miranda confirms this Sicilian concentration and adds important cores in Calabria, Lombardy, Lazio, Piedmont, Liguria, Veneto, Friuli-Venezia Giulia, Emilia-Romagna and the Marche.