Ostuni, a picturesque walled city of Apulia, Italy, in the province of Lecce, 23 m. by rail N.W. of Brindisi. Pop. (1901) 7734 (town); 22,811 (commune). It has a cathedral of the 15th century with a fine Romanesque façade, and a municipal library with a collection of antiquities. The see has been amalgamated with that of Brindisi.