Julio Salvador Sagreras (22 November 1879 – 20 July 1942) was an influential Argentine guitarist, composer, and pedagogue. Born in Buenos Aires, he was introduced to the guitar at an early age by his parents, both of whom were guitarists. Sagreras began performing in concerts at the age of six. By the age of twelve, he had expanded his musical education to include piano and composition. His rapid progress in music led him to become a professor of guitar at the Académia de Bellas Artes in 1899.

In Buenos Aires, Sagreras met Francisco Nuñez, an editor who published around a hundred of his compositions. In 1905, Sagreras founded his own music school, the Academia de Guitarra. Between 1900 and 1936, he was active in performing, giving numerous concerts in concert halls and salons, and participating in radio broadcasts.

Sagreras is particularly renowned for his comprehensive guitar instruction series, consisting of seven books designed to guide students from beginner to advanced levels. These instructional books are noted for their methodical approach and clarity, allowing students to potentially teach themselves.

Among his notable compositions are "Maria Luisa" (a mazurka), "El Zorzal" (Estilo), "Violetas" (Waltz), and the virtuosic "El Colibri." Sagreras' contributions to guitar pedagogy and his compositions have left a lasting impact on classical guitar music.