He returned to command of the 5th Division on 30 August 1813, and was immediately severely wounded again in the bloody but victorious assault at the Siege of San Sebastián on 31 August. For his services in the Peninsula, Leith was awarded the Army Gold Cross and clasp for Corunna, Busaco, Badajoz, Salamanca, and San Sebastian. On 2 February 1814 he received permission to accept and wear the insignia of an Honorary Knight Commander of the Order of the Tower and Sword, awarded to him by the Prince Regent of Portugal.