Constant Lievens (11 April 1856 – 7 November 1893) was a Belgian (Flemish) Jesuit priest, missionary among the tribal peoples of Central India, particularly the Mundaris, Oraons.

After a few months of preliminary contacts and study of the language and customs of the Munda people Lievens settled in a hut at Torpa, a large village 60 km south of Ranchi (today's capital city of the Jharkhand state).

He began gathering information on the tribal customary law and started defending in the English colonial courts the rights of those whose land had been taken away by deceit.

His own rural background made him understand without difficulty how much land was an important factor in the self-dignity and identity of the tribal populations of the Chotanagpur plateau, in particular the Mundas, Oraons and Kharias.

Appointed Director of the Mission he shifted residence to Ranchi (1888-1892), the district headquarters, from where coordination of missionary activities (justice and social work, education and evangelization) was easier done.

Suffering from tuberculosis, he was sent by doctors to the mountains of Darjeeling (end of 1891), but the urgency of the work - and disquieting news of apostasies - brought him hurriedly back to the Chota Nagpur where he again spent himself without counting.