Raja Bahadur Kamakhya Narain Singh (10 August 1916 – 1970) of Ramgarh, Jharkhand was the zamindar of Ramgarh Raj and later a politician.
He was educated at Rajkumar College, Raipur and at Mayo College, Ajmer. He became the Raja of Ramgarh in 1919 upon death of his father, Raja Lakshmi Narain Singh. He served as the Vice-President of the Bihar Landholder's Association and the All India Kshatriya Mahasabha. He was also Member of the Managing Committee and General Council of Rajkumar College; Member of the Executive Body of the Bihar War Committee. He served as president of Akhil Bharatiya Kshatriya Mahasabha in 1943 and 1953.
He was married to Maharani Lalita Rajya Lakshmi Devi, daughter of Supradipta Manyabara Lt.Gen. Maharajkumar Singha Shumsher Jung Bahadur Rana of Nepal in 1936. They had a son, Indra Jitendra Narain Singh.
He entered politics in 1946 following the formal accession of the Ramgarh state into the Indian Republic. In 1952 Bihar Assembly elections, he contested from Dhanbad as a candidate of Swatantra Party but was defeated by a noted freedom-fighter and labor rights leader, Purushottam K. Chauhan. Later in the Bihar Assembly Elections of 1967, serious opposition was offered by the Raja Bahadur's Swatantra Party to the ruling Congress government. The Raja Bahadur and his younger brother, Dr. Basant Narayan Singh, became Cabinet Ministers in the government headed by Chief Minister of Bihar, Mahamaya Prasad Sinha. He resigned from the party because he was not made the Deputy Chief Minister. In late 1960s, Kamakhya Narayan Singh was popularly an aspirant for Rajput supremacy in Bihar against Rajput stalwart, Sri Satyendra Narain Singh (then known as "Coming Chief Minister of Bihar") but was outmanoeuvred. His party later merged with the Janata party. Many of his family members became important political functionaries and legislators.