Thottuvelil Krishna Pillai Ayappan Nair (born in 1939) is a career civil servant who formerly served as Adviser to the Prime Minister of India with the rank of the Minister of State. He also previously served as Principal Secretary to Prime Minister of India. He is a 1963 batch Indian Administrative Service officer from Punjab Cadre. He also presently serves as Member of Board of Governors of Indian Institute of Management Kozhikode and . He formerly served as Chairman of Kerala State Industrial Development Corporation.