Mariana de Pineda (September 1, 1804–May 26, 1831) was a Spanish woman.

She married very young to Manuel Peralta Valte , a liberal army officer, and widowed in 1822 with 2 children. She became very involved in liberal causes. In 1828 she assisted the escape from prison of her cousin, Captain Fernando Alvarez de Sotomayor , a noted liberal who had been condemnded to death for taking part in General Rafael Riego's insurrection.

In a search of her house in 1831, a flag was discovered with the embroidered slogan 'Equality, Freedom and Law' and she was arrested and accused of conspiracy. After a failed escape attempt she was detained in the Santa María Egipciaca convent in Granada. During the trial, the Judge tried to convince her to betray her accomplices in exchange for leniency, but she refused and was publicly executed on May 26.

In 1925 the playwright Federico García Lorca based his play Mariana Pineda on her story, turning the popular heroine into legend and myth.