Colonel Henry Steel Olcott (2 August 1832 – 17 February 1907) was an American military officer, journalist, lawyer, Freemason and the co-founder and first president of the Theosophical Society.

Olcott was the first well-known American of European ancestry to make a formal conversion to Buddhism. His subsequent actions as president of the Theosophical Society helped create a renaissance in the study of Buddhism. Olcott is considered a Buddhist modernist for his efforts in interpreting Buddhism through a Europeanized lens.

Olcott was a major revivalist of Buddhism in Sri Lanka and he is still honored in Sri Lanka for these efforts. Vice President of the Ananda College Old Boys Association Samitha Seneviratne has said that “Col. Olcott’s contribution towards the betterment of our country, nation, religion, justice and good conduct has been so great that he remains in our hearts forever”
During his time in Ceylon, Olcott strove to revive Buddhism within the region, while compiling the tenets of Buddhism for the education of Westerners. It was during this period that he wrote the Buddhist Catechism (1881), which is still used today.With a sense of pride we have to point out to the country that as a result of pursuing the thinking of Col. Olcott, Colombo Buddhist Theosophical Society was able to establish 460 Buddhist schools, including leading colleges such as Ananda, Nalanda, Dharmapala, Dharmaraja, Mahinda, Dharmashoka, Maliyadewa, Rahula, Visakha Musaeus, and Mahamaya.