Jack Milton Fields Jr. (born February 3, 1952) is an American businessman and a former Republican member of the United States House of Representatives from a Houston-based district.

After being admitted to the Texas bar in 1977, Fields worked as a lawyer in private practice and as a vice president of a family-owned business through 1980.

In 1980, at the age of twenty-eight, Fields was elected to the U.S. House on the coattails of President Ronald Reagan's electoral victory.

He narrowly defeated 8th District incumbent Bob Eckhardt, a seven-term Democrat, by only 4,900 votes to become the first Republican to represent what is now the 8th in 83 years.

Instead, he started two companies, the 21st Century Group, Inc., a government relations firm based in Washington, D.C., and Texana Global, Inc., an international trade corporation headquartered in Texas.