Charles Lathrop Parsons (March 23, 1867, New Marlboro, Massachusetts-February 13, 1954 Pocasset, Massachusetts) was an American chemist.

For nearly forty years, Parsons served as executive secretary of the American Chemical Society, becoming known as "Mr. ACS" and substantially influencing the formation of the association.

[7][8] In addition to his research, Parsons took an active interest in the history of the American Revolution and published a book in 1903 about the Capture of Fort William and Mary.

He was sent to Europe to study the fixation of nitrogen and oxidation of ammonia, which were important for the production of fertilizer and explosives.

[1] Parsons became a member of the American Chemical Society (ACS) when he attended the World Congress of Chemists at the Columbian Exposition of 1893 in Chicago.

[2] From 1919 to 1946, Parsons was full-time executive secretary of the ACS, its chief administrative officer, in charge of its day-to-day operations.

He was also involved with the creation of a number of divisions, organized around specialized groups, beginning with Industrial Chemists and Chemical Engineers.

[2] In addition, Parsons served as secretary of Section C of the American Association for the Advancement of Science (AAAS) from 1904 to 1908.

He served as vice president for America of the International Union of Pure and Applied Chemistry (IUPAC), from 1919 to 1922.

In 1932 he received the Priestley Medal for distinguished service, the highest honor conferred by the American Chemical Society.

[13] The Charles Lathrop Parsons Award of the American Chemical Society is named in his honor and was first presented, to him, in 1952.