The origin of the ethnonym Lezgin requires further research. Nevertheless, most researchers attribute the derivation of Lezgi to be from the ancient Legi and early medieval Lakzi.
Modern-day Lezgins speak Northeast Caucasian languages that have been spoken in the region before the introduction of Indo-European languages. They are closely related, both culturally and linguistically, to the Aghuls of southern Dagestan and, somewhat more distantly, to the Tsakhurs, Rutuls, and Tabasarans (the northern neighbors of the Lezgins). Also related, albeit more distantly, are the numerically small Jek, Kryts, Laks, Shahdagh, Budukh, and Khinalug peoples of northern Azerbaijan. These groups, together with the Lezgins, form the Samur branch of the indigenous Lezgic peoples.
Lezgins are believed to descend partly from people who inhabited the region of southern Dagestan in the Bronze Age. However, there is some DNA evidence of significant admixture during the last 4,000 years with a Central Asian population, as shown by genetic links to populations throughout Europe and Asia, with notable similarities to the Burusho people of Pakistan.
Prior to the Russian Revolution, the Lezgins did not have a common self-designation as an ethnic group. They referred to themselves by village, region, religion, clan, or free society. Before the revolution, the Lezgins were called "Kyurintsy", "Akhtintsy", or "Lezgintsy" by the Russians. The ethnonym "Lezgin" itself is quite problematic. Prior to the Soviet period, the term "Lezgin" was used in different contexts. At times, it referred only to the people known today as Lezgins. At others, it referred variously to all of the peoples of southern Daghestan (Lezgin, Aghul, Rutul, Tabasaran, and Tsakhur); all of the peoples of southern Daghestan and northern Azerbaijan (Kryts Jek, Khinalug, Budukh, Shahdagh); all Nakh-Daghestani peoples; or all of the indigenous Muslim peoples of the Northeast Caucasian peoples (Caucasian Avars, Dargwa, Laks, Chechens, and Ingush). In reading pre-Revolutionary works, one must be aware of these different possible meanings and the scope of the ethnonym "Lezgin".