Newmar appeared in several low-budget films during the next two decades. She guest-starred on TV, appearing on The Love Boat, Buck Rogers in the 25th Century, CHiPs, and Fantasy Island. She was seen in the music video for George Michael's "Too Funky" in 1992 and appeared as herself in a 1996 episode of Melrose Place.
In 2003, Newmar appeared as herself in the television movie Return to the Batcave: The Misadventures of Adam and Burt alongside former Batman co-stars Adam West, Burt Ward, Frank Gorshin, and Lee Meriwether. Julia Rose played Newmar in flashbacks to the production of the television series. However, due to longstanding rights issues over footage from the Batman TV series, only footage of Meriwether taken from the feature film was allowed to be used in the television movie. In 2016, she provided the voice of Catwoman in the animated film Batman: Return of the Caped Crusaders. In 2017, she reprised her role in the animated sequel Batman vs. Two-Face. Newmar also appeared on The Home and Family Show in May 2016, where she met Gotham actress Camren Bicondova who portrays a younger Selina Kyle.
In 2019, Newmar played the role of Dr. Julia Hoffman (replacing the late Grayson Hall) in the audio drama miniseries, Dark Shadows: Bloodline