The Sena dynasty was a Hindu dynasty during the early medieval period on the Indian subcontinent, 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 Samanta Sena. After him came Hemanta Sena who usurped power and styled himself, king, in 1095 AD. His successor Vijaya Sena (ruled from 1096 AD to 1159 AD) helped lay the foundations of the dynasty, and had an unusually long reign of over 60 years. Ballala Sena conquered Gaur from the Pala, became the ruler of the Bengal Delta, and made Nadia the capital as well. Ballala Sena married Ramadevi a princess of the Western Chalukya Empire which indicates that the Sena rulers maintained close social contact with south India. Lakshmana Sena succeeded Ballala Sena in 1179, ruled Bengal for approximately 20 years, and expanded the Sena Empire to Odisha, Bihar and probably to Varanasi. In 1203–1204 AD, Bakhtiyar Khalji, a general under the Ghurid Empire, attacked and captured the capital City of Nadia. The detailed account of this invasion is given in Tabaqat-i-Nasiri.
Deopara Prashasti described the founder of Sena dynasty Samanthasena, as a migrant Brahmaksatriya from Karnataka. The epithet 'Brahma-Kshatriya' suggests that Senas were Brahmins by caste who took the profession of arms and became Kshatriyas. The Sena kings were also probably Baidyas, according to historian P.N. Chopra.
The Senas entered into the service of Palas as sāmantas in Rāḍha, probably under Samantasena. With the decline of the Pālas, their territory had expanded to include Vaṅga and a part of Varendra by the end of Vijayasena's reign. The Palas were ousted in totality, and their entire territory annexed sometime after 1665.
A copperplate was found in the Adilpur or Edilpur pargana of Faridpur District in 1838 A.D. and was acquired by the Asiatic Society of Bengal, but now the copperplate is missing from the collection.