Mrityunjay Kumar Singh (born 30 August 1961) is an IPS Officer of the 1987 batch belonging to the West Bengal Cadre. He is also a poet, columnist, lyricist and folk musician.
 Mrityunjay Kumar Singh, also known as MK Singh, was born in 1961 in Sonbarsa, Bihar. He was brought up in the rural environs of Western Bihar, a land rich and ripe with crops and culture.
 As Superintendent of Police, Murshidabad he worked for safety, security and conservation of the Hazar Duari palace and museum of Murshidabad in West Bengal, being maintained by the Archaeological Survey of India in 1997–98.
 He also worked simultaneously as the Director of the Branch Secretariat of Ministry of External Affairs, Kolkata dealing with consular, border and bilateral and multilateral diplomatic matters related to Bangladesh, Bhutan and Nepal.
 MK worked with NGOs of India and Bangladesh dealing with illegal child trafficking and migration across International border and their restoration and reintegration with their families from 2003 to 2007.
 He also represented India in UNICEF's multilateral discussion on illegal trafficking and migration of Children across International borders in South Asia held in Kathmandu, Nepal in 2007.
 MK represented India as a member of the Working Committee to formulate scope and objectives of 'Bali Democracy Forum'(a multilateral forum to discuss and deliberate on development & implementation of democracy and its ethics) in December 2008.
 As Counsellor of the Embassy of India, Jakarta and Director of Jawaharlal Nehru Indian Cultural Centre, Jakarta and Indian Cultural Centre, Bali, worked to innovate ways for breaking new grounds of people to people contact, collaborations, sharing and deeper understanding of diverse views and cultures. Hosted a very successful 'Festival of India' in Indonesia in 2009–10 (held after 7 years) with 48 events in 7 cities of Indonesia under the supervision of the Ambassador of India to Indonesia. Commended by the Indian Ambassador for the said feat.
 After completing his tenure as Counsellor (culture), Embassy of India, Jakarta and Director of the Jawaharlal Nehru Indian Culture Centre of Jakarta as well as Indian Culture Centre, Bali, he has returned to his cadre (West Bengal) in India in 2011 and is presently working as Commandant General & Director General of Police (Home Guards), West Bengal.
 MK is married to Manjula Singh, who worked as lecturer of Political Science in University of Delhi, Loreto College, Darjeeling (from 1986 to 1993)and as a Consultant to the National Centre for Jute Diversification, Ministry of Textiles, Government of India for a project jointly funded by UNDP and Government of India (from 2004 to 2008). She is also associated with the management of 'Sarada Kalyan Bhandar', a NGO working with the women and children of nine villages of Midnapore in the state of West Bengal since 1998. Manjula is working as the Advisor for the Eastern India Health Initiative (a CSR activity of Medica Super speciality Hospital of Kolkata).
 He has two sons – Ishaan Singh and Shaunak Singh.
 MK is living and working in Kolkata (West Bengal), India.
 MK's song Uphaar was featured in the Hindi film Dharm (2007) and Via Darjeeling (2008), also a Bengali film called Chokher Bali.