Henry Ralph Mahler (1921–1983) was an Austrian-born American biochemist known for his research in the fields of both mitochondrial biogenesis and neurochemistry.

At Berkeley, he conducted research on aspects of mechanism of photosynthesis in plant chloroplasts under the direction of Nobel Prize winner Melvin Calvin.

In the 1976–77 academic year, he served as an honor fellow at University College London, a visiting professor at the C.N.R.S.

[2] During Professor Mahler's career, he published more than 300 research articles with his many former students, postdoctoral fellows and colleagues.

He also coauthored two editions (1966 and 1971) of a well known textbook Biological Chemistry with his colleague Professor Eugene H. Cordes.