William Trigg Gannaway (June 10, 1825 – June 5, 1910) was an American educator.
He served as president pro tempore of Duke University (at the time named "Trinity College") during the absence of Braxton Craven in 1864-1865, and was a professor there for some 35 years, starting in 1857 and ending in 1892.
He was a Professor of Latin, Greek, and philosophy at Trinity College.
Gannaway was born in Wythe County, Virginia.
He received his diplomas from Emory and Henry College in 1847.
He then opened a high school at Floyd Court House, Virginia.
From 1854 to 1857, Gannaway operated a high school in Germantown, North Carolina.He died at his farm in Randolph County, North Carolina.