John F. Yardley (February 1, 1925 – June 26, 2001) was an American engineer who worked for the McDonnell Aircraft Corporation and the National Aeronautics and Space Administration (NASA).

In 1968, he became vice president and deputy general manager of the Eastern Division of McDonnell-Douglas Astronautics, and worked on Project Apollo and Skylab.

After the inaugural flight of the Space Shuttle in 1981, he returned to McDonnell-Douglas as president of its McDonnell Douglas Astronautics subsidiary, a position he held until he retired in 1989.

He was known for "Yardley's Law": "Pretty is what works", his response to someone who said that the Mercury spacecraft looked like a waste paper bin.

[1] He graduated from high school in 1942 when he was sixteen years old, and was awarded a scholarship to Washington University in St. Louis, where he studied mechanical engineering.

[1] In the late 1950s, McDonnell began working on the design of spacecraft, starting with an unsuccessful bid for the United States Air Force's Dyna Soar.

Yardley left NASA after the first successful flight of the Space Shuttle in 1981, and returned to St. Louis and McDonnell-Douglas as president of McDonnell Douglas Astronautics, a position he held until he retired in 1989.