Josiah Morris Slemons (1879–1948) was an American physician who researched and wrote on issues of pregnancy and prenatal nutrition.

Slemons remained at Johns Hopkins for his internship and residency (1901-1904), as well as beginning his medical career as an instructor and then an assistant professor (1904-1913).

In addition, he published a number of research papers on the biochemistry of the fetal circulatory system and the placenta (see Bibliography).

At the end of World War I, Slemons and his wife traveled to France with the American Red Cross as part of a team of specialists.

Their purpose was to provide education on prenatal hygiene and fetal nutrition in an effort to increase the birth rate, which had dropped precipitously during the war.