Abstract: The present invention provides various amorphous forms of the compound metaxalone (I), such as solid amorphous metaxalone and amorphous dispersions comprising metaxalone. The present invention further provides pharmaceutical compositions comprising these amorphous forms, and methods of their preparation. The present invention additionally provides methods of treating painful conditions (e.g., such as painful musculoskeletal conditions) comprising administering a therapeutically effective amount of any one of these amorphous forms to a subject in need thereof.