Luís Fróis (1532 – 8 July 1597) was a Portuguese missionary.
He was born in Lisbon and in 1548 joined the Society of Jesus (Jesuits). In 1563, he arrived in Japan to engage in missionary work, and in the following year arrived in Kyoto, meeting Ashikaga Yoshiteru who was then shōgun. In 1569, he befriended Oda Nobunaga and stayed in his personal residence in Gifu while writing books for a short while. His works on history were somewhat expanded by Joāo Rodrigues. Among his works was the Treatise (1585) on the contrast of morals between Europe and Japan (Tratado em que se contêm muito sucinta e abreviadamente algumas contradições e diferenças de costumes entre a gente de Europa e esta província de Japão).
Frois witnessed the end of Nobunaga, from his church across the street from Honno-ji, writing an account afterward.