Jacob Akiba Marinsky (April 11, 1918, Buffalo, New York – September 1, 2005) was a chemist who was the co-discoverer of the element promethium.

He attended the State University of New York at Buffalo, beginning at age 16[3] and receiving a bachelor's degree in chemistry in 1939.

[4] In 1945, together with Lawrence E. Glendenin and Charles D. Coryell, he isolated the previously undocumented rare earth element 61 (promethium).

[3] He resumed his education after the war, obtaining a PhD in Nuclear and Inorganic Chemistry from the Massachusetts Institute of Technology in 1949.

[4] His research was concerned with nuclear inorganic chemistry, physicochemical studies of ion exchange, and polyelectrolyte and electrolyte systems.