China’s Muslim Uighurs have recently proven to be an unusual source of friction in the stalwart Sino-Pakistan friendship. In this article from Asian Survey Ziad Haider analyzes how politics in the Xinjiang Uighur Autonomous Region and trade and movement along the Karakoram Highway linking Xinjiang with Pakistan have affected the relationships among Beijing, Islamabad, the Uighurs, and the Pakistani traders operating in Xinjiang.