Elektra, Op. 58, is a one-act opera by Richard Strauss, to a German-language libretto by Hugo von Hofmannsthal, which he adapted from his 1903 drama Elektra. The opera was the first of many collaborations between Strauss and Hofmannsthal. It was first performed at the Dresden State Opera on January 25, 1909.

Elektra is a difficult work and is musically complex. A performance requires musicians with great stamina. The role of Elektra in particular is one of the most demanding in the dramatic soprano repertoire.

Despite being based on ancient Greek mythology, the opera is highly modernist and expressionist. Hofmannsthal and Strauss's adaptation of the story focuses tightly on Elektra, thoroughly developing her character by single-mindedly expressing her emotions and psychology as she meets with other characters mostly one at a time. The other characters are Klytaemnestra, Elektra's mother and one of the murderers of Agamemnon, Elektra's father; her sister, Chrysothemis; her brother, Orestes; and Klytaemnestra's lover, Aegisthus. None of them show much development; all are secondary to the story.

Everything else from the myth is minimized as background to Elektra's character and her obsession. Other aspects of the ancient story are completely excluded, tightening the focus on Elektra's furious lust for revenge. The result is a very modern, expressionistic retelling of the ancient Greek myth. Compared to Sophocles's Electra, the opera presents raw, brutal, violent, and bloodthirsty horror.