Edwin Mattison McMillan (September 18, 1907 – September 7, 1991) was the first scientist to produce a transuranium element.

He was born in Redondo Beach, California. He received his Bachelor of Science degree in 1928 and his Master of Science degree in 1929, both from the California Institute of Technology; he then took his Doctor of Philosophy from Princeton University in 1932.

He joined the staff of the University of California, Berkeley upon receiving his doctorate, moving to the Berkeley Radiation Laboratory when it was founded at Berkeley in 1934.

In 1940 he created neptunium using the cyclotron at Berkeley. In World War II, he was involved in research on radar, sonar, and nuclear weapons. In 1945 he developed ideas for the improvement of the cyclotron, leading to the development of the synchrotron.

With Glenn T. Seaborg, he shared the Nobel Prize in Chemistry in 1951 for the creation of the first transuranium elements.

In 1946, he became a full professor at Berkeley, and in 1954 he was appointed associate director of the Lawrence Radiation Laboratory, being promoted to director in 1958, where he stayed until his retirement in 1973.

He was elected to the National Academy of Sciences in 1947, serving as its chairman from 1968 to 1971.