The simple, usually opposite leaves of Jamesbrittenia breviflora are stalked. The leaf-shape is oval in outline, the margins shallowly scalloped or sometimes entire. The tips are bluntly pointed to rounded, the bases square to lobed. The midribs and ascending lateral veins that split near the margins are all sunken on the upper surfaces, giving the blades a quilted appearance. Glandular hairs are present on the blades. The leaves are up to 35 mm long and well narrower (Manning, 2009; Pooley, 1998; iNaturalist; https://pza.sanbi.org).