Harold Hooper (known almost universally as just Mr. Hooper) was a character on Sesame Street who was the original proprietor of Mr. Hooper's Store, which still retains his name.

When the actor who played him, Will Lee , died in 1982, rather than replace him with another actor, the character was also killed off. Sesame Street devoted an episode to Mr. Hooper's death.

In that episode, which aired in November 1983 (early in the series' 15th season), Big Bird plans to give a drawing of Mr. Hooper to his friend. When he is unable to find Mr. Hooper, the adults remind him that Mr. Hooper has died. Big Bird initially refuses to accept this news, but as the adults assure him they are telling him the truth, Big Bird grieves over the loss of his friend (and the adults, who also miss Mr. Hooper, mourn with him). By the end of the episode, Big Bird accepts the fact that Mr. Hooper is not coming back and has gained an understanding about what death is; however, he also is taught that he will always have many happy memories to remember his friend. The portrait of Mr. Hooper that Big Bird had planned to give him still hangs in Big Bird's nest. The episode ended with a brief montage of clips featuring Mr. Hooper from earlier seasons (along with acknowledgement of Will Lee 's passing).

Mr. Hooper is Jewish, according to Christmas Eve on Sesame Street. In true Sesame Street fashion, his religion was irrelevant to all other plots, although there was an episode of the show in which Big Bird enquires about the languages that various members of the community can speak. Mr. Hooper reveals that he was taught to read, write and speak Yiddish at after-school religious instruction.

For some reason that was never really explained, Big Bird had trouble saying "Hooper", instead using various words that rhymed with it, such as "Looper" or "Crouper". This led to frequent retorts of "Hooper! Hooper!" from Mr. Hooper whenever Big Bird missaid his surname. His forename was revealed on the March 15, 1976 episode (#871), in which he received his GED.