Melicope balloui is a small tree or shrub species reaching heights of 4 to 7 meters. The new growth is covered with a yellowish-brown tomentose layer and waxy scurf but becomes glabrate as it matures. The leaves are simple and opposite, with blades that are obovate to elliptic, measuring 5–10 cm long and 3–7 cm wide. The leaf apex is emarginate, and the base is broadly cuneate or rounded. Surfaces are initially puberulent but become glabrate except along the midrib on the lower surface. The blades are coriaceous, with margins entire. The primary lateral veins number about 9–14 pairs and are connected by a vein 2–3 mm from the margin. The venation is pinnate, with lateral veins connecting to an arched submarginal vein and higher-order venation forming a reticulate pattern. Petioles are 10–26 mm long, and stipules are absent. The flowers are arranged in yellowish-green, appressed puberulent, axillary cymes, typically 5–9 per cyme. The peduncles are 3–16 mm long, and the pedicels are about 5 mm long, with small, opposite bracts. Flowers are functionally unisexual, and the plants are monoecious. The calyx consists of four imbricate sepals, ovate, around 3 mm long, densely appressed puberulent, with acute apices. The corolla also has four petals, valvate, approximately 4 mm long, similarly densely puberulent with acute tips. Both sepals and petals are usually persistent in fruit. Staminate flowers are unknown. The ovary is superior, densely puberulent, 4-celled, and 4-lobed, with carpels connate except slightly distinct at the apex. Each cell contains two ovules, hemitropous, with one ascending. The single style terminates in four short stigmatic branches. The fruit is a capsule measuring 25–27 mm wide, with carpels connate about a quarter of their length and each carpel about 12–13 mm long. The exocarp is puberulent, and the endocarp is uniformly sparsely puberulent. Seeds are 1–2 per carpel, about 7 mm long, glossy black when ripe, ovoid, and sometimes angled from compression. The seeds have a crustaceous putamen that is brown and warty, and an embryo that is straight within fleshy endosperm, with a short radicle and compressed, ovate cotyledons. It is known only from wet forest habitats between 1,280-1,520 meters.