Montagu Christie Butler (25 January 1884 – 5 May 1970) was a British academic, librarian, lexicographer, musician, and Esperantist.

As a Quaker and absolute pacifist, Butler was classed as a conscientious objector during World War One.

From 1922, Butler was a member of the Lingva Komitato, the group tasked with preserving the fundamental principles of the Esperanto language and guiding its evolution.

Butler served as editor of La Brita Esperantisto ("The British Esperantist") in 1931 and 1932; during his editorship the journal became known as one of the most famous Esperanto periodicals of the era.

The collection of Esperanto and Esperanto-related books he assembled during his lifetime now forms the heart of the Butler Library, which the BEA established at Wedgwood Memorial College in Staffordshire, England, and named in his honour.