Joseph Lawrence Pfeifer (February 6, 1892 – April 19, 1974) was a United States Representative from New York. Born in Brooklyn, he attended St. Nicholas Parochial School, St. Leonard's Academy, and St. Francis College in Brooklyn. He graduated from Long Island Medical College in 1914 and was licensed to practice the same year. He was a lecturer and author on surgical topics and during the First World War he served on the medical advisory board, instructing medical officers going overseas.
Pfeifer was elected as a Democrat to the Seventy-fourth and to the seven succeeding Congresses (January 3, 1935 – January 3, 1951).
A confidential 1943 analysis of the House Foreign Affairs Committee by Isaiah Berlin for the British Foreign Office stated that Pfeifer
Has a mixed record on foreign policy. 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. Age 51. 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.