Jean O'Brien Dickey (31 October 1945 – 9 May 2018) was an American scientist. Dickey was a pioneering geodesist and particle physicist with expertise in Earth rotation. After receiving a PhD from Rutgers University, she spent much of her career at NASA's Jet Propulsion Laboratory (JPL). Between 1994 and 1996, she served as President of the American Geophysical Union's geodesy section, the first woman to hold that position.