The narrow leaves of Osteospermum monstrosum, grown long at the base of the plant, are oblanceolate, their tips rounded. The deep green blades are sparsely hairy, the midribs visible. The leaf margins are toothed, sometimes lobed. The basal leaves may be 6 cm long and 3 cm wide.
The smaller stem-leaves are alternate, usually widely spaced (Vlok and Schutte-Vlok, 2010; Manning, 2007; Le Roux, et al, 2005; Bond and Goldblatt, 1984; iNaturalist).