William Thacher Longstreth (November 4, 1920 – April 11, 2003) was a Republican member of the Philadelphia City Council who was perhaps best known for his long tenure and unique image.

He was also instrumental in the creation of the Greater Delaware Valley Chapter of the National Multiple Sclerosis Society.

While a member of City Council, he served as a sideline reporter on Philadelphia Eagles radio broadcasts on WIP in 1969 and 1970.

[citation needed] Longstreth was again elected to Council in 1983, defeating incumbent councilwoman Beatrice Chernock for the at-large seat he had vacated twelve years earlier to run for Mayor.

During his tenure on Council, Longstreth helped support the efforts of Edmund Bacon to bring an urban renaissance to Philadelphia.