Gregory J. Markopoulos (March 12, 1928 - November 12, 1992) was an American experimental filmmaker. Born in Toledo, Ohio to Greek immigrant parents, Markopoulos began making 8 mm films at an early age. He attended USC Film School in the late 1940s, and went on to become a co-founder — with Jonas Mekas, Shirley Clarke, Stan Brakhage and others — of the New American Cinema movement. He was as well a contributor to Film Culture magazine, and an instructor at the Art Institute of Chicago.

In 1967, he and his partner Robert Beavers left the United States for permanent residence in Europe. Once ensconced in self-imposed exile, Markopoulos withdrew his films from circulation, refused any interviews, and insisted that a chapter about him be removed from the second edition of Visionary Film, P. Adams Sitney's seminal study of American avant-garde cinema. While he continued to make films, his work went largely unseen for almost 30 years.

"[Markopoulos] was the son of Greek immigrants from the Peloponnesus and spoke only Greek until the age of six. The ancient legends and orthodox spirituality of that tradition would prove a grounding matrix for the rest of his life. The concomitant isolation and displacement he surely felt, being homosexual and son of foreigners marooned in the vast American heartland was equally important to his aesthetic evolution. He could sense the world as a ‚heap of fragments’, intuit life as a ‚perrenial exile.’ Having produced his first 8mm film at the age of twelve, as a brilliant young high school student he considered pursuing medical training, with an eye to surgery, but applied instead to several film production schools, even one in Russia, finally enrolling at the University of Southern California, Los Angeles, just at the end of WWII. There, he attended the master classes of Josef von Sternberg and was a student-observer to studio productions directed by emigrés Lang, Hitchcock, Curtiz and Korda. He also met future Sci-Fi director Curtis Harrington at this time, sharing with him an interest in the uses of exotic color and the hypnagogic literature of the ‚poetes maudits’. He was fascinated by the idea of synesthesia, the confusion and correspondence between impressions of different senses that had pre-occupied many Romantic artists, among them Wagner, Rimbaud and Scriabin." - Kirk Alan Winslow