Josiah Parsons Cooke (October 12, 1827 – September 3, 1894) was an American chemist who worked at Harvard University and was instrumental in the measurement of atomic weights, inspiring America's first Nobel laureate in chemistry, Theodore William Richards, to pursue similar research.

He attended Boston Latin School and as a teenager set up his own chemical laboratory, partly due to an interest sparked by lectures of Yale's Benjamin Silliman.

The teaching of chemistry at Harvard was in poor shape at this time,[3] so after Cooke entered the university in 1843 he continued to be largely self-taught in the subject.

Reversing the modern order, after Cooke obtained his professorship he embarked on a plan of advanced study, spending eight months in Europe attending the lectures of Dumas and Regnault.

[4] On returning to the United States, Cooke began in earnest to raise the standard of chemical education at Harvard, introducing required courses in chemistry, accompanied by laboratory instruction.