The sources differ on the etymology of this surname. E. Rossoni proposes two hypotheses: that it derives directly from the Greek mythological name Dorus or Dora —Dorus was son of Neptune and Ellepis, and from him took their name the Dorians, a Greek people to whom is also attributed the language called Doric—, or that it is an apocopated form of compound names such as Isidoro, Medoro, Teodoro or similar.

V. Blunda, on the other hand, derives it from the Greek dora, meaning "gifts, presents". According to this author, the term designated the offerings and gave rise to the surname through a feminine personal name of good augury applied to a female ancestor, within the habitual patterns of Greek onomastics preserved in the tradition of the Byzantine Mediterranean. Blunda documents it in Sicily.

Rossoni records a scattered geographical distribution. The form Dora is very rare, with presence in the Brescia area and in the Naples area. Dori appears in specific zones of the Venice area, in Romagna and Tuscany, and between Rome and the Frosinone area. The form Doro is documented in the Veneto, in Genoa, in Rome, in the Taranto area and in Sardinia, both in the Sassari area and in Cagliari.