Victor Frederick "Viki" Weisskopf (also spelled Viktor; September 19, 1908 – April 22, 2002) was an Austrian-born American theoretical physicist.

His brilliance in physics led to work with the great physicists exploring the atom, especially Niels Bohr, who mentored Weisskopf at his institute in Copenhagen.

[5] One of his few regrets was that his insecurity about his mathematical abilities may have cost him a Nobel Prize when he did not publish results (which turned out to be correct) about what became known as the Lamb shift.

[8] There, he met graduate student Esther Conwell, and together they formulated the Conwell–Weisskopf theory, which describes the movement of electrons through semiconductors and led to a better understanding of integrated circuits, knowledge that became essential for modern computing.

As the Red Scare faded, in 1959 Weisskopf joined physicists George Gamow and Hans Bethe in supporting the return of exiled physicist Frank Oppenheimer to science teaching;[10]: 130  a decade later, Oppenheimer would found the innovative Exploratorium museum of science, technology, and arts in San Francisco.

In a joint statement "Preserving and Cherishing the Earth" with other noted scientists including Carl Sagan, it concluded that: "The historical record makes clear that religious teaching, example, and leadership are powerfully able to influence personal conduct and commitment ...

Weisskopf died on April 22, 2002, and was survived by his second wife Duscha, daughter of accidental Night of the Long Knives victim Willi Schmid.