Rebecca Luker (April 17, 1961 – December 23, 2020) was an American actress, singer, and recording artist, noted for her "crystal clear operatic soprano" and for maintaining long runs in Broadway musicals over the course of her three-decade-long career. The New York Times compared her to actresses such as Barbara Cook and Julie Andrews.

Beginning in regional theatre productions in the early 1980s, Luker made her Broadway debut in the original cast of The Phantom of the Opera as a Christine understudy and later took over the role as the principal actress. She would then originate the role of Lily in The Secret Garden on Broadway in 1991. She was nominated for three Tony Awards, for her performances as Magnolia in Show Boat (1994), Marian in The Music Man (2000) and Winifred in Mary Poppins (2006), another role that she created. She performed widely in theatre throughout her career and also gave concert and cabaret performances. She began acting in television in 2000 and made several films. Luker continued to act until the year of her death, at the age of 59, from amyotrophic lateral sclerosis. She can be heard on more than 20 cast albums and various other recordings.