Bobbi Adler, Grace's mother, played by Debbie Reynolds. Bobbi is an actress and singer, although her performances are generally with the Schenectady Players, changing gender roles, in plays such as Death of a Salesperson, The Music Person and Queen Lear. She has a constant desire to meddle in the lovelives of her daughters, is the creator of the Adler family "Told you so" dance, and can always be relied upon to have a song for every occasion. She has, in the past, shown perfect willingness for Will and Grace to get married, despite their sexuality differences.

Martin Adler, Grace's father, played by Alan Arkin. Portrayed by his family as the stereotypical Jewish patriarch, Martin shows genuine affection for Grace, although remarks he has made suggest Joyce is his favorite. Has been known to pinpoint Grace's flaws without looking up from his Kojak and Baretta reruns.

Janet Adler, Grace's older sister, played by Geena Davis. Janet lives in a van and designs jewelery. Her nickname for Grace is "smudge." It is once implied that she has difficulties with her mother, for in the episode "Lows in the Mid-Eighties," Will asks if Grace has another sister named Janet, and Bobbi quickly answers "No!"

Joyce Adler, Grace's younger sister, played by Sara Rue. It is suggested that she is mentally slow and that she was formerly a binge eater.