The Insubres or Insubri were a Gaulish or Italic population settled in Insubria, in what is now the Italian region of Lombardy. They were the founders of Mediolanum (Milan). Though culturally Celtic at the time of Roman conquest (at the beginning of the 2nd century BC), they were most likely the result of the fusion of pre-existing Ligurian, Celtic, Etruscan, and Italicpopulation[citation needed] (such as the Golasecca culture) strata with Gaulish tribes who had come from what is now southernFrance.

The Insubres are mentioned by Cicero, Polybius, Livy, Pliny the Elder, Strabo and Caecilius Statius.

The Roman historian, Livy, wrote about the Insubres. According to his writings all of Northern Italy (between the northern and western Alpine watershed, the rivers Adda and Oglio at the east and Emilian Apennine to south) suffered in the course of centuries of repeated invasions by Celtic tribes from the region of Gaul. He claimed that before the invasion of the 4th century BC there was a previous one, dated around the late 7th and early 6th century BC.