Ambika Charan Choudhury (16 August 1930 – 4 December 2011), popularly known as Kamataratna,[1] was an Indian litterateur, historian and activist, known for his contributions to the Assamese literature.

[3][5] He was actively involved with the Sanmilita Jatiya Abhibartan, which is facilitating the peace process between Government of India and the moderate wing of the rebel group ULFA.

Ambika Choudhury started his major literary journey through Ratnapeethot Ebhumiki, a book written in 1961.

[4][1] Koch-Rajbanshi Jatir Itihakh aru Sanskriti, Kamatapurot Mohapurush Sreemanta Sankardev, Xantirdut Hajrat Mohammad, The Koches Around the World, Koch-Rajbanshies betrayed, Biswabir Chila Roy Sahitya Pratibha, Rani Abhayeswari and Bijni Rajyar Itibritta are some of his notable books written in Assamese and English.

He was regarded the backbone of Koch-Rajbanshi language movement and was conferred the title of Kamataratna by many cultural and literary organisations.