Bettina von Arnim (the Countess of Arnim), born Elisabeth Catharina Ludovica Magdalena Brentano, was a German writer and novelist.

Bettina (as well: Bettine) Brentano was a writer, publisher, composer, singer, visual artist, an illustrator, patron of young talent, and a social activist. She was the archetype of the Romantic era's zeitgeist and the crux of many creative relationships of canonical artistic figures. The sister of Clemens Brentano and wife of his friend Achim von Arnim, today she is best known for the company she kept, having numbered among her closest friends Goethe, Beethoven, and Pückler and tried to foster artistic agreement among them. Many leading composers of the time, including Robert Schumann, Franz Liszt, Johanna Kinkel, and Johannes Brahms, admired her spirit and talents. As a composer, von Arnim's style was unconventional, molding and melding favorite folk melodies and historical themes with innovative harmonies, phrase lengths, and improvisations that became synonymous with the music of the era.