Brotherhood of the Bolt is a generic fantasy horror role-playing game supplement published in 1983 by The Companions, the third in the five-part "Islandia Campaign" series.

John Wheeler, through their company The Companions, had previously published two adventures in the "Islandia Brotherhood Campaign", The Curse on Hareth (1982), and Plague of Terror (1983).

Brotherhood of the Bolt was the third in this series, a 40-page book with three maps published in 1983,[3]: 160  written by Rice and Wheeler with additional material by Ray Estabrook, Donna McKinnon, William R. Mohler, Matthew Needham, and Dennis O'Brien.

The artwork was by Rice and Wheeler as well as John Carlson, Tom Cobb, Mary Coman, David J. Hutchins, Kevin LaChance, Matthew Needham, and Eric Pfusch.

[4] Ken Rolston reviewed this product twice in the pages of Dragon: In Issue 23 of Imagine, Mike Dean pointed out that because of the adventure's complexity and the necessity of adapting it to a role-playing system, it "will provide your group with many sessions of play, but only if you are prepared to put in the necessary time and work for conversion and full understanding of the plots running through each of them.