Lawrence Randolph Hafstad (June 18, 1904 – October 12, 1993) was an American electrical engineer and physicist notable for his pioneering work on nuclear reactors and development of proximity fuzes.

In 1931, he earned the American Association for the Advancement of Science Prize for his research with Merle A. Tuve and Odd Dahl.

During that same period, he was executive secretary of the research and development board at the Department of Defense.

From 1949 to 1955, he served as director of reactor development with the United States Atomic Energy Commission.

[4][1][10] Hafstad died on October 12, 1993, at his home in the Oldwick section of Tewksbury Township, New Jersey.