Gary Gygax and Mary Jo Hyatte divorced after many years of marriage. They had five children together: Ernie, Heidi, Elise, Cindy, and Luke.

Gygax married Gail Carpenter. This marriage provided him with renewed support during a turbulent period in his career with TSR.

Gary and Gail maintained a private family life, supporting each other's endeavors, including his gaming work and her interests. They remained married until his death.

Gygax enjoyed being a grandfather. His family, including his children and grandchildren, remained a significant part of his life.