Ambrosio Martínez Bustos (1614-1672) was a Spanish Baroque painter active in Granada.
Born in and resident of Granada, Martínez Bustos was from a wealthy family, and was trained in the studio of Miguel Jerónimo de Cieza. According to his marriage certificate he married on February 8, 1635. Cieza's workshop was one of the busiest and most prestigious in Granada. He was initially influenced by Flemish painting through known prints, as seen in his Inmaculada at the Museo de Bellas Artes de Granada. His specialty was the major theme of the Immaculate Conception, on which he produced several copies (church of St. Andrew, St. Cecilio and St. Scholastica, Museum of Fine Arts, Casa de los Tiros and others). He also is known to have collaborated with Pedro Atanasio Bocanegra and Cieza for the ephemeral decorations for the celebration of Corpus Christi.