The dark green leaves of Thunbergia neglecta grow in spaced, opposite pairs. Their stalks are from 1 cm to 3 cm long. Here the leaves have a somewhat angular to square, heart-shaped base, more lobed than toothed along their wavy margins.

The leaf sometimes shows two teeth on each side. Leaf hairiness seems to have disappeared from mature leaves while stems, stalks and calyces retain theirs (Pooley, 1998; Van Wyk and Malan, 1997; iNaturalist).