Alexander Solomon Wiener (March 16, 1907 – November 6, 1976), was an American biologist and physician, specializing in the fields of forensic medicine, serology, and immunogenetics.

His work led to the discovery of the Rh factor in 1937, along with Karl Landsteiner, and subsequently to the development of exchange transfusion methods that saved the lives of infants with hemolytic disease of the newborn.

[1] During his time in medical school Wiener did research work on blood groups at the Jewish Hospital of Brooklyn and from 1930 to 1932 he interned there and kept up a lifelong affiliation with that institution as the head of the Division of Genetics and Biometrics (1933–1935) and as the head of the blood transfusion division until 1952.

In recognition of his contribution to forensic medicine he was awarded an honorary membership of the Mystery Writers of America.

Numerous articles and chapters of books with real life crime stories were written about Dr. Wiener's work in criminology.

Wiener helped draft a new set of laws addressing the recent scientific advancements in blood identification.

He was a member of the American Medical Association legal committee that sponsored blood test laws in all states, and he was the co-author of its 1935 report.

When Wiener and Landsteiner discovered the Rh factor in 1937 (named after the Rhesus monkeys used as test subjects), they did not immediately realize its significance.

By the time he and Landsteiner published in 1940, Wiener was able to demonstrate the role of Rh sensitization as a cause of intragroup hemolytic reactions, thus increasing the safety of blood transfusions.