Ad Astra is an annual science fiction, fantasy, and horror convention in Ontario.

Other events on the convention program include a games room, book launches, and the Saturday evening dance.

Ad Astra's programming features a wide variety of discussion panels on various topics of interest to science fiction and fantasy fans.

In previous years, guests have included prominent Canadian writers including Robert J. Sawyer, Nalo Hopkinson, Tanya Huff, Guy Gavriel Kay, Robert Charles Wilson, Phyllis Gotlieb, etc., as well as internationally renowned authors including C. J. Cherryh, David Brin, Connie Willis, Stephen Hunt, Larry Niven, Lois McMaster Bujold, Frederik Pohl, Katherine Kurtz, Orson Scott Card, James P. Hogan and others.

Ad Astra has continued to evolve past its focus on literature to include programming dedicated to costuming, art, filking, and media.