Juan Diego Ruiz Moreno (14 December 1942 – 28 April 2022), professionally known as Juan Diego, was a Spanish actor who appeared on stage, in television and film productions since 1957. He starred in films such as The Holy Innocents, The 7th Day, Dragon Rapide, París-Tombuctú and You're the One.

Performing with a raspy voice for much of his career, he is often associated with abrupt, violent, and authoritarian roles, having a knack for nailing fascist-like characters. His most known television role was the foul-mouthed Don Lorenzo in Los hombres de Paco, popular for the idiom ¡Mis santos cojones!

Also known for his left-wing political activism, Juan Diego took part in the struggle for advancing film workers' labor rights in Spain.

Juan Diego Ruiz Moreno was born on 14 December 1942 in Bormujos, and spent his childhood there. He made his acting debut in theatre in 1957. Key stage credits throughout his career include performances in plays such as Olvida los tambores, El lector por horas, La gata sobre el tejado de zinc, and Yo me bajo en la próxima, ¿y usted?

After studying performing arts in Seville, Juan Diego moved to Madrid in order to develop his acting career, featuring in Televisión Española shows (most notably in plenty of Estudio 1 plays), likewise making his film debut in Eloy de la Iglesia's Fantasía... 3 (1966).

Having joined the then clandestine Communist Party of Spain in the late 1960s, Juan Diego had a leading role in organizing the 1975 Spanish actors strike. The first of his two children was born in 1970. His left-wing political activism did not end upon the death of dictator Francisco Franco, but continued during the Transition and beyond. Decades later, he would also be seen demonstrating in Spain against the Iraq War.

Diego starred as Marcos, a popular television host and member of a post-Francoist party (and scorned husband), alongside Ana Belén and a big black dog in a love triangle in the 1977 zoophilia-themed film La criatura.

He landed a breakthrough role with his performance in Mario Camus' 1984 film The Holy Innocents, playing Señorito Iván, a repulsive authoritarian landlord from an Extremaduran cortijo, obsessed with game hunting and disdainful of his workers. He earned his first Goya Award nomination at the first edition of the awards celebrated in 1987, for his leading role as Francisco Franco in the period drama Dragon Rapide, which tracks the early stages of the Spanish Civil War. He portrayed a moor in the film The Bastard Brother of God. He earned another best actor nomination for his role as Saint John of the Cross in the 1989 film The Dark Night, his first collaboration with Carlos Saura.