An H. P. Lovecraft Encyclopedia is a reference work written by S. T. Joshi and David E. Schultz. It covers the life and work of American horror fiction writer H. P. Lovecraft. First published in 2001 by Greenwood Publishing Group, it was reissued in a slightly revised paperback edition by Hippocampus Press.

The book provides entries on all of Lovecraft's stories, complete with synopses, publication history and word counts. People from Lovecraft's life, including selected writers who influenced his work, are also included.

Fictional characters from Lovecraft's work are given brief entries, but most Cthulhu Mythos-related subjects are not referenced. "The 'gods' themselves, with rare exceptions, do not figure as 'characters' in any meaningful sense in the tales, so there are no entries on them," the authors explain.