The Ilmen Slavs (Russian: Ильменские словене) was the northernmost tribe of the Early East Slavs, which inhabited the shores of the Lake Ilmen and the basin of the rivers of Volkhov, Lovat, Msta, and the upper stream of the Mologa River in the 8th to 10th centuries.

The Ilmen Slavs seem to have been different from other Slavic tribes colonizing what is now Russia in that they were closely related to the Polabian Slavs in language and traditions (see old Novgorod dialect and Gostomysl for examples). They settled mostly Finnic areas in Northern Russia, moving along the major waterways, until they met the southward expansion of the Krivichs in the modern-day Yaroslavl Oblast.

They left a few archaeological monuments of the 6th–8th centuries, such as agricultural settlements and tall conelike kurgans with incinerated bodies in the Ladoga region. The most ancient settlement is dated back to the 7th or 8th century. Numerous archaeological finds, such as a metal tip for a wooden plough, indicate that the Ilmen Slavs had a well-developed agriculture. They were not a particularly warlike state, but evidence of their unique weaponry, dated back to mid-8th Century, has been found around the city of Novgorod. The weaponry consisted of spears, maces, swords, bows, javelins and even some war hammers. It would seem that they fought rather aggressive warfare designed to push their enemies out of their lands, rather than destroy them utterly.