Joseph L. Mayer (c. 1875 − 1 December 1933) was an American chemist.
He was born in New York City, and had two sisters, Dora and Hannah, and a brother, Fred.
His first job as a pharmacist was as a drug clerk for Benjamin Rosenzweig.
He worked on the 1920 revision of the United States Pharmacopoeia.
His scientific articles appeared in the Journal of the American Pharmaceutical Association, and elsewhere.