Oswald Thompson Allis (September 9, 1880 – January 12, 1973) was an American Presbyterian theologian and Bible scholar.

Later, Allis received an honorary Doctor of Divinity degree from Hampden Sydney College in 1927.

Allis taught in the Department of Semitic Philology at Princeton Theological Seminary (1910–1929).

In 1929, Allis, J. Gresham Machen, Robert Dick Wilson and others founded Westminster Theological Seminary.

Allis was independently wealthy and it was his property in Philadelphia which initially served as the home of the new seminary.