Elmina Drake Slenker (born Elizabeth Drake, December 23, 1827 – February 1, 1908) was a 19th-century American author, leader in the Freethought movement, and early sex reformer. A regular contributor to anarchist journal Lucifer the Lightbearer, Slinker advocated a sexual practice called Dianism. In 1887, Slenker was arrested for violating the Comstock laws which criminalized use of the US postal service to deliver sexually explicit content. She was jailed for several months, subjected to jury trial, and found guilty before finally being freed on a technicality.