The Mountain Institute (TMI) is an international non-profit organization headquartered in Washington, D.C., and operates regional field offices in the Andes,[1] Appalachians,[2] and Himalayas.

[3] Respectively, these are the longest, the oldest, and the tallest mountain ranges in the world.

TMI is the sole organization dedicated to conservation and development in mountain regions.

In 1973, TMI's work expanded to experiential and leadership education for youth.

TMI became an international organization in 1987, when it assisted in the establishment of Makalu Barun National Park in Nepal and the adjacent Qomolangma National Nature Preserve in the Tibet Autonomous Region of China.