Helen Mossler, CSA, is a casting executive for Paramount Television. In this position, she was the long-time casting executive for Star Trek, beginning with the first season of Star Trek: The Next Generation in 1987 and ending with the second season of Star Trek: Enterprise in 2003, after which she was replaced by Christine L. Smith and then by Sheila Guthrie.
In addition to Star Trek, Mossler served as casting executive on such shows as Frasier (starring Kelsey Grammer), Becker (starring Terry Farrell), and Soul Food (starring Vanessa Williams), as well as a number of made-for-TV movies. She has also served as casting director on a number of TV projects, including the Showtime series Brothers, for which she and Star Trek III: The Search for Spock casting director Mary Ann Barton received an Artios Award nomination from the Casting Society of America (CSA) in 1985. Mossler herself became a member of the CSA in 1990.