The Sena Empire (Bengali: সেন সাম্রাজ্য, Shen Shamrajjo) was a Hindu dynasty that ruled from Bengal through the 11th and 12th centuries. The empire at its peak covered much of the north-eastern region of the Indian subcontinent. The rulers of the Sena Dynasty traced their origin to the south Indian region of Karnataka.

The dynasty's founder was Hemanta Sen, who was part of the Pala Empire until it began to weaken. Hemanta Sen usurped power and styled himself king in 1095 AD. His successor Vijay Sen (ruled from 1096 AD to 1159 AD) helped lay the foundations of the dynasty, and had an unusually long reign of over 60 years. Ballal Sena conquered Gaur from the Pala, became the ruler of the Bengal Delta, and made Nabadwip the capital as well. Ballal Sena married Ramadevi a princess of the Western Chalukya Empire which indicates that the Sena rulers maintained close social contact with south India.Lakshman Sen succeeded Ballal Sena in 1179, ruled Bengal for approximately 20 years, and expanded the Sena Empire to Assam, Odisha, Bihar and probably to Varanasi. In 1203–1204 AD, the Turkic general Bakhtiyar Khilji attacked Nabadwip. Khilji defeated Lakshman Sen and captured northwest Bengal - although Eastern Bengal remained under Sena control.

The political space after the decline of the Pala power in Bengal was occupied by the Senas whose king Vijayasena succeeded in conquering a large part of Pala territory. The Senas were the supporters of orthodox Hinduism. The dynasty traces its origin to the South, to the Western Chalukya Empire of southern India. Theres is a record of a Western Chalukya invasion during the reign of Someshvara I led by his son Vikramaditya VI who defeated the kings of Gauda and Kamarupa. This invasion of the Kannada ruler brought bodies of his countrymen from Karnataka into Bengal which explains the origin of the Sena Dynasty.

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