Glycosmis longisepala is a tree of Borneo in the family Rutaceae. The specific epithet ' is from the Latin meaning "long sepal".
Glycosmis longisepala grows as a small tree. The leaves measure up to long. The inflorescences measure up to long. The fruits measure up to long.
Glycosmis longisepala is endemic to Borneo where it is confined to Mount Pueh in Sarawak. Its habitat is forests at around elevation.