Charles Johnston (17 February 1867 – 16 October 1931) was an Irish writer, journalist, theosophist, naturalist, and Sanskrit scholar. Johnston joined the Indian Civil Service in 1888 but left India after two years due to malaria and settled in the United States of America in 1896. He wrote numerous books on Indian philosophy, translating works from Sanskrit as well as on Theosophy. He was married to the niece of Madame Blavatsky and was involved in the development of the Theosophical Society in the United States.