C8H8N2O3S, Mr = 212.54, monoclinic, P2(1)/a, a = 7.347 (9), b = 13.237 (4), c = 10.128 (8) A, beta = 108.916 (6) degree, V = 931.9 (1) A3, Z = 4, Dm = 1.52 (4), Dx = 1.514 g cm-3, lambda (Cu K alpha) = 1.54184 A, mu = 28.35 cm-1, F(000) = 440, room temperature, R = 0.040 for 1864 observed reflections. The sulfonamide N forms intermolecular hydrogen bonds with the benzisoxazole ring N and also with the O on the sulfonamide group. Centrosymmetrically related benzisoxazole ring pairs are pi bonded with a high degree of overlap.