The Brown Wood Owl is medium large (45-57 cm), with upperparts uniformly dark brown, with faint white spotting on the shoulders. The underparts are buff with brown streaking. The facial disc is brown or rufous, edged with white and without concentric barring, and the eyes are dark brown. There is a white neckband. The sexes are similar.

The call is a (hoo) hoo hoo HOO or a deep goke-goke-ga-LOOO or a loud scream. The alarm call is a bark, wow-wow. Some subspecies are known to produce distinct vocalizations; they are also different in appearance and parapatric, and might be distinct species