The consulted works agree that the surname Macchia belongs to a broad onomastic family that includes numerous variants such as Macchi, Macchini, Macconi, Macci, Maccio, and Macchitella, among others. This diversity of forms reflects the overlapping of different linguistic and cultural traditions over time.

E. Rossoni identifies several possible etymological origins. The most widely accepted is toponymic or geographical: the Italian term macchia, meaning "scrub," "low wood," or "thick vegetation," derives from the Latin macula ("stain"), and the surname would originally have designated those who lived near such Mediterranean landscapes or who came from localities bearing that name. A Celtic origin has also been proposed, from makos ("wood"), consistent with the presence of these surnames in areas of northern Italy where ancient Celtic influences existed.

Rossoni further notes a Latin and literary derivation linked to the name Maccus, a character from the ancient Atellan comedies, represented as a simple, gluttonous, or guileless individual. This figure was popularized by authors such as Plautus — whose full name was Titus Maccius Plautus — and his name may have generated personal forms such as Macco or Maccius, from which several modern surnames could derive. It is considered, in the source Surnames in Italy, that the surname may indeed stem from a variant of the old personal name Macco, from the Latin Maccus, which appears frequently in medieval documents, or alternatively as a variant of Macchia itself.

Rossoni additionally points to the role of aphaeresis: some forms may derive from the truncation of more complex medieval names ending in -macco, such as Buffalmacco or Burlamacco — the latter mentioned by Boccaccio in the Decameron — reflecting the phonetic simplifications typical of the medieval period. From these various roots, numerous variants developed through suffixes, diminutives, augmentatives, and dialect adaptations, with rarer forms such as Macchitelli or Macchitello possibly arising from local fixings or transcription errors.