Ernest Karlovich Drezen (14 November 1892 – 27 October 1937) was a Soviet Esperantist (i.e. a proponent of the artificial international language Esperanto) and engineer.

[2] Drezen was also a member of the Sennacieca Asocio Tutmonda, though he was critical of their methods and ultimately expelled as part of the opposition in 1931.

[5] He was arrested along with other members of the SEU on 17 April 1937 as part of the Great Purge to eliminate potential political enemies of Joseph Stalin, and he was executed by gunshot on 27 October 1937.

[2] He opposed the inclusion of anarchists and social democrats in the Esperantist community, and he was critical of the Sennacieca Asocio Tutmonda for being insufficiently Communist.

[8] He believed that Esperanto's status of an international language among the workers must be established before a worldwide socialist movement could be undertaken.