Rosario Sansores Prén (25 August 1889 – 7 January 1972) was a Mexican poet and journalist, known for works such as "Cuando tú te hayas ido" ("When You Have Gone"), a poem that served as the basis for the pasillo-style song "Sombras" ("Shadows"), by Ecuadorian composer Carlos Brito.

She was born in a well-off family, the daughter of Juan Ignacio Sansores Escalante and Laura Prén Cámara, who tried to dissuade her from writing poetry at a young age.

She subsequently published works of poetry such as Mientras se va la vida (While Life Is Going) (1925) and Rutas de emoción (Routes of Emotion) (1954).

Years later the poem was read by Ecuadorian composer Carlos Brito Benavides, who set the lyrics to music in order to create the song "Sombras" ("Shadows").

In fact, she was only in Ecuador once, in 1967, when she was the guest of honor of the Guayaquil Association of Journalists, received a literary award, and was declared a gold poet by President Otto Arosemena.