Alois Greil was an Austrian painter and illustrator.

Greil came from a Tyrolean family of artists. He was supported by Adalbert Stifter and in 1857 received a scholarship to the Academy of Fine Arts in Vienna. He studied there with Christian Ruben and devoted himself primarily to history painting. In 1867 he returned to Linz, but lived in Stuttgart in 1868/69 and in Vienna from 1873. He painted peasant motifs and landscapes in watercolours, contributed historical and contemporary representations of clothing for the sheets for costume studies and painted genre pictures.

In his early work he is inspired by the work of Peter Fendiand his students, in his mature phase around 1870 his oeuvre follows the style of Moritz von Schwind and Carl Spitzweg, sometimes also that of the Düsseldorf school of painting. From 1878 to 1885 he was President of the Albrecht Dürer Association (Society of Academics). From 1870 to 1880 he worked as an illustrator for Die Gartenlaube. He also illustrated the Neue Illustrierte Zeitung, the Brockhaus encyclopedia and numerous complete editions of poetic works, for example by Ludwig Anzengruber, Eduard von Bauernfeld, Franz Grillparzer and Robert Hamerling, Peter Rosegger, Adalbert Stifter and Johann Nepomuk Vogl.