The Sicambri (also Sugambri) were a Germanic people who lived in the area between the Rhine, Lippe, and Wupper rivers, in what is now Germany, near the border with the Netherlands. They were first reported by Julius Caesar, who encountered them in 55 BC. They became a significant opponent of Roman imperial power in the Rhine region. After a major defeat by the Romans in 8 BC a significant part of the Sicambri were moved into Roman territory.
Caesar categorized them as a Germanic people (Germani), although he did not necessarily define ethnicity in terms of language. Whether or not the Sicambri spoke a Germanic or Celtic language, or something else, is not certain. They lived in a contact zone where these two language families came into contact and were both influential.
By the 3rd century, the region in which they and their neighbours had lived had become part of the territory of the Franks, which was a new name that possibly represented a new alliance of older tribes, possibly including the Sicambri. However, many Sicambri had been moved into the Roman empire by this time.