Encyclopedias, Almanacs, Transcripts, and Maps
- Third World Women's Alliance
- Thirteen Colonies, British North America
- Thirteen Years' War
- Thirteenth Amendment to the U.S. Constitution
- Thirty Years War (1618–1648)
- Thirty-Eighth Parallel
- Thomas Boone Pickens, Jr
- Thomas Clement Douglas
- Thomas Edward Lawrence
- Thomas Henry Kendall
- Thomas Ince
- Thomas J. J. Altizer
- Thomas Jefferson
- Thomas Kennerly Wolfe Jr
- Thomas Moran
- Thomas Octave Murdoch Sopwith
- Thomas of Woodstock
- Thomas Roderick Dew
- Thomas Starzl
- Thomas Stoppard