Lee McLeod Janzen (born August 28, 1964) is an American golfer who is best known for twice winning the U.S. Open, in 1993 and 1998.

Janzen was born in Austin, Minnesota, and spent most of his childhood in Baltimore, Maryland, where he played Little League baseball. When Janzen was 12, his father's company transferred him to Florida and his parents started him in golf and tennis, and he continued playing baseball. Janzen liked golf best and started playing that sport exclusively. He won his first tournament at age 15 as a member of the Greater Tampa Junior Golf Association.

Janzen chose to attend a small college – Florida Southern – rather than a big institution like Florida. In 1985 and 1986, Florida Southern won the Division II national team championship. Janzen was the individual medalist in 1986. He turned professional later that same year.