Harriett Everard (12 March 1844 – 22 February 1882) was an English singer and actress best known for originating the role of Little Buttercup in the Gilbert and Sullivan hit H.M.S. Pinafore in 1878. The character regretfully reveals a key secret that sets up the ending of the opera.

Everard had a stage career of 20 years, although she died at the age of 37. She appeared, for the first 15 of these, in numerous burlesques, pantomimes, comic operas, comic plays and even some dramas. She played in a few of W. S. Gilbert's early plays before becoming part of Richard D'Oyly Carte's company at the Opera Comique, creating the role of Mrs. Partlett in The Sorcerer as well as the part of Little Buttercup. She was scheduled to originate the role of Ruth in The Pirates of Penzance, but she was forced to withdraw after an onstage accident during a rehearsal that caused her serious injury. She returned to the stage, briefly, but it is said that she never fully recovered.