Melicope affinis is a tree that typically grows to a height of but also forms flowers and fruit as a shrub. The leaves are trifoliate and arranged in oppositepairs on a petiole long, the leaflets usually elliptical, long and wide, the end leaflet on a petiolule long. The flowers are bisexual and arranged in panicles or long in leaf axils. The sepals are egg-shaped to round, about long and fused at the base. The petals are greenish white, about long and glabrous and there are four stamens. Flowering has been observed in March and the fruit consists of up to four follicles long.