Silene lanceolata is a subshrub with erect to ascending stems, measuring 15–50 cm long, essentially glabrous, and often swollen at the nodes. The leaves are simple and can be opposite or whorled, with oblanceolate to linear or lanceolate blades measuring 25–80 mm long and 2–11 mm wide. The leaf apex is acute to acuminate, and the base is often connate around the stem, gradually tapering to the base. The leaf surfaces are ciliate toward the base and otherwise glabrous, with entire margins. Stipules are absent. The flowers are arranged in open, paniculate, or corymbose cymes and are glabrous to sparsely pubescent throughout. The flowers are bisexual (perfect) and actinomorphic (radially symmetric), with 8–23 mm long pedicels. The calyx is 5-toothed, measuring 7–9 mm long, with ten nerves, and is glabrous to sparsely pubescent, with obtuse lobes and scarious margins. The corolla consists of 5 white petals, with blades approximately 6 mm long, notched, and with a 2-lobed scale at the base. The stamens are included in the calyx tube. The ovary is superior, 1-celled or incompletely 2–4 celled, on a well-developed stipe that is adnate to the staminal filament bases and petal bases, referred to as a carpophore. There are 3 (sometimes 4–5) styles, and the carpophore measures 1–2 mm long. The fruit is an oblong, ovoid capsule, 3-celled in the lower part, measuring 8–9 mm long, and dehisces by six or rarely three apical teeth or valves. The seeds are reddish brown, reniform, about 1 mm long, and papillose. It is known from relatively dry areas to mesic shrubland between 330 – 1,900 meters.