The Old Assyrian period was the second stage of Assyrian history, covering the history of the city of Assur from its rise as an independent city-state under Puzur-Ashur I c. 2025 BC to the foundation of a larger Assyrian territorial state after the accession of Ashur-uballit I c. 1363 BC, which marks the beginning of the succeeding Middle Assyrian period. The Old Assyrian period is marked by the earliest known evidence of the development of a distinct Assyrian culture, separate from that of southern Mesopotamia and was a geopolitically turbulent time when Assur several times fell under the control or suzerainty of foreign kingdoms and empires. The period is also marked with the emergence of a distinct Assyrian dialect of the Akkadian language, a native Assyrian calendar and Assur for a time becoming a prominent site for international trade.

Assyria was a major ancient Mesopotamian civilization which existed as a city-state from the 21st century BC to the 14th century BC, then to a territorial state, and eventually an empire from the 14th century BC to the 7th century BC.