Although it is little known, there is a community of Muslims in Tibet. Islam first arrived in Tibet in the 1200s when merchants came up from Kashmir. They settled and formed a community, which has continued until today. When the Chinese began colonizing Tibet in 1959, after putting down the Tibetan National Uprising, many of Tibet's Muslims fled to Kashmir where they were eventually granted Indian citizenship. A large number of these live with the Tibetan community in exile there, while others have spread to other areas in India or abroad.
The website of the Tibetan government in exile has several pages on Tibetan Muslims including Muslims of Tibet, a historical overview, Staunch Muslims, Tibetans at Heart, a profile of the community, and a picture gallery. Additional information is available at Historical Sketch of the Muslims of Tibet. There is also a book about Tibetan Muslims, with a forward by the Dalai Lama, called Islam in Tibet: Tibetan Caravans.