James T. Kirk quoted from King Lear in 2270, after telling Kukulkan that his assistance to mankind was not required, by stating the lines from Act I scene IV: "How sharper than a serpent's tooth it is / To have a thankless child!" (TAS: "How Sharper Than a Serpent's Tooth")
Background information Edit
In 2002, Star Trek: The Next Generation star Patrick Stewart portrayed Lear in a modernized TV movie adaptation of the play, entitled King of Texas, which also featured Colm Meaney and Richard Lineback. Stewart (alongside his wife, Wendy Neuss) also served as executive producer on the project.
Early drafts of Star Trek: Insurrection had Picard distract Data in the Federation mission scoutship by quoting from King Lear. It was Patrick Stewart who suggested using Gilbert and Sullivan instead. (Fade In: From Idea to Final Draft)