Solomon Adler (August 6, 1909 — August 4, 1994) was an economist in the U.S. Treasury Department who served as Treasury representative in China during World War II. He was identified by Whittaker Chambers and Elizabeth Bentley as a Soviet intelligence source and resigned from the Treasury Department in 1950. After several years teaching at Cambridge University in England, he returned to China, where he resided from the 1960s until his death, working as a translator and economic advisor. Beginning in the early 1960s, Adler was also affiliated with the Central External Liaison Department, an important Chinese Communist Party organ whose functions include foreign intelligence.
Solomon Adler was born on 6 August 1909 in Leeds, England. The Adler family was of Jewish ancestry and originally from Karelitz, Belarus, moving to Leeds in 1900. Solomon Adler was the fifth of ten children; the oldest was Saul Adler, who became a well-known Israeli parasitologist. Adler studied economics at Oxford and University College, London. He came to the United States in 1935 to do research. In 1936 he was hired at the Works Progress Administration's National Research Project, but soon moved to the Treasury Department's Division of Monetary Research and Statistics, where he worked with Harry Dexter White for the next several years.
Adler became a naturalized United States citizen in 1940. In 1941, he was posted to China, where he remained as Treasury representative until 1948. His reports from China to Treasury secretary Henry Morgenthau, Jr. during the war years were widely circulated and played an important role in shaping American wartime economic policy toward China.
In 1949, Adler became the subject of a Loyalty of Government Employees investigation. He resigned before the case was resolved and returned to Britain, where he taught for several years at Cambridge University. When his American passport expired, he was denaturalized and lost his American citizenship. Adler moved to China in the early 1960s, working in the lead group of the team translating Mao Zedong's works into English.