Dyskolos (Greek: Δύσκολος, pronounced [dýskolos], translated as The Grouch, The Misanthrope, The Curmudgeon, The Bad-tempered Man or Old Cantankerous) is an Ancient Greek comedy by Menander, the only one of his plays, and of the whole New Comedy, that has survived in nearly complete form. It was first presented at the Lenaian festival in Athens in 316 BC, where it won Menander the first prize.

It was long known only through fragmentary quotations; but a papyrus manuscript of the nearly complete Dyskolos, dating to the 3rd century, was recovered in Egypt in 1952 and forms part of the Bodmer Papyri and Oxyrhynchus Papyri. The play was published in 1958 by Victor Martin.

The story of the play concerns a rich young man, Sostratos, who falls in love with a village girl, whose father, Knemon, is very bad-tempered and hard to approach. Eventually, after helping Knemon's stepson Gorgias to rescue him from a well, he wins Knemon over and gains his assent to marry his daughter. He also persuades his own father to allow him to betroth his own sister to Gorgias.

The Dyskolos inspired Molière, who knew only the theme of the play, as it had not yet been found, in his writing of The Misanthrope (1666).