Pi Delta Theta (ΠΔΘ) was a national collegiate sorority operating in the United States from February 14, 1926, until it was absorbed by Delta Sigma Epsilon in September 1941.

She invited representatives of three organizations to send their faculty advisors to a meeting in Boston, Massachusetts in the summer of 1925.

Expansion began in earnest, but early chapters were lost as the Great Depression dragged on.

In 1941, with WWII looming, the four remaining chapters opted for merger.

[3] Pi Delta Theta was a member of the Association of Education Sororities, an NPC predecessor.