Joseph Lawrence Pfeifer (February 6, 1892 – April 19, 1974) was an American physician and politician who served as a member of the United States House of Representatives for New York's 8th congressional district from 1935 to 1951.

He graduated from Long Island College of Medicine in 1914 and was licensed to practice the same year.

He dissented on (1) lifting of arms embargo; (2) neutrality revision; (3) extension of conscription; (4) lifting of belligerent zones; but on other major issues of foreign policy, such as conscription, Lend-Lease (and the various appropriations for it) and the repeal of the ban on arming United States ships, he supported the Administration.

Internationalist.Pfeifer was an unsuccessful candidate for renomination in 1950 to the Eighty-second Congress and resumed the practice of medicine.

He retired and resided in Brooklyn, where he died in 1974; interment was in St. John's Cemetery, Middle Village.