"The Cruel Angel's Thesis" , also known as "A Cruel Angel's Thesis", is a J-pop song performed by Japanese singer Yoko Takahashi. Toshiyuki Ōmori and Hidetoshi Satō composed the song, while Neko Oikawa wrote the lyrics. It was written for the opening theme of the anime television series Neon Genesis Evangelion, and was released as a double-A-sided single with "Fly Me to the Moon", the show's closing theme, on October 25, 1995. "The Cruel Angel's Thesis" was also included in the series' soundtrack releases and Takahashi's albums.

Yoko Takahashi is a Japanese singer, who is best known for her work throughout the 1990s, most particularly for her singles which were performed for and featured in anime, most notably the Neon Genesis Evangelion franchise.