The H. P. Lovecraft Historical Society or HPLHS is the organization that hosts Cthulhu Lives!, a group of live-action roleplayers for the Cthulhu Live version of Call of Cthulhu. Founded in Colorado in 1984, it is now based in Glendale, California. Their motto is Ludo Fore Putavimus ("We thought it would be fun").
HPLHS is well known for producing a number of Cthulhu Mythos films and sound recordings, under its Mythoscope and Mythophone labels.