Rudolph Maurice Loewenstein (January 17, 1898 – April 14, 1976) was an American psychoanalyst who practiced in Germany, France, and the United States.

He was a founding member and also secretary of the first French psychoanalytic society, the Société psychanalytique de Paris (SPP).

(Some of the other founding members included René Laforgue, Marie Bonaparte, Raymond de Saussure, and Angelo Hesnard.)

In 1927, he participated in the creation of the SPP's journal, the Revue française de psychanalyse [fr]; and in 1928 he and Marie Bonaparte translated Freud's case-study of Dora into French.

[5] In 1930, he became a French citizen by decree and obtained his medical license anew - defending his thesis for a doctorate in medicine in 1935.