Guido Menasci (March 24, 1867 - December 27, 1925) was an Italian opera librettist.
His best known work is Cavalleria rusticana written with Giovanni Targioni-Tozzetti. He also provided the libretti for Mascagni's I Rantzau, Zanetto, for Umberto Giordano's Regina Diaz and Viktor Parma's Stara pesem (Old Song).
Menasci was born in Livorno.