Following its tour of duty at Aldershot, the regiment rotated to India in 1859. After serving at various Indian stations, the 99th was called to active service to form part of General Sir Hope Grant's force during the Second Opium War. Assigned to the 2nd Division, commanded by Major-General Sir Robert Napier, the 99th took part in the Third Battle of Taku Forts and the Battle of Palikao. The regiment also participated in the Sack of Peking, where among the loot carried off, the regiment took a Pekinese dog that belonged to the Chinese Empress. The dog, named Lootie, was taken back to England where it was presented to Queen Victoria. For its service in China, the regiment earned the battle honour: Pekin 1860. Rather than return the 99th to India, the regiment was ordered to join the Hong Kong garrison, securing the new Kowloon territory acquired by the Convention of Peking. The regiment would remain in Hong Kong until 1865.