Benjamin Lee Whorf (April 24, 1897 - July 26, 1941) was an American linguist.

Born in Winthrop, Massachusetts the son of Harry and Sarah (Lee) Whorf, Benjamin Lee Whorf graduated from the Massachusetts Institute of Technology in 1918 with a degree in Chemical Engineering and shortly afterwards began work as a fire prevention engineer (inspector) for the Hartford Fire Insurance Company, pursuing linguistic studies as an avocation. Although he met, and later studied with Edward Sapir (1884-1939), he never took up linguistics as a profession, though his contribution to the field was profound.

Whorf's primary area of interest in linguistics was the study of native American and Mesoamerican languages. He became quite well known for his work on the Hopi language, and for a theory he called the Principle of Linguistic Relativity. Developed in conjunction with Sapir (who had already published a version of it in 1929) it became more widely known as the Sapir-Whorf Hypothesis. He was considered to be a captivating speaker and did much to popularize his linguistic ideas through popular lectures and articles written to be accessible to lay readers, as well as publishing numerous technical articles.

Some of Whorf's early work on linguistics and particularly on linguistic relativity was inspired by the reports he wrote on insurance losses, where misunderstanding had been a cause. In one famous example, an employee who was not a native speaker of English had placed drums of liquid near a heater, believing that as a 'flammable' liquid would burn then a 'highly inflammable' one would not. His papers and lectures featured examples from both his insurance work and his fieldwork with Hopi and other American languages.

The Sapir-Whorf Hypothesis primarily dealt with the way that language effects thought. Also sometimes called the Whorfian hypothesis (much to Whorf's disapproval) this theory claims that the language a person speaks (independent of the culture in which it resides) affects the way that they think, meaning that the structure of the language itself affects cognition.

Benjamin Lee Whorf died of cancer at the relatively young age of 44, and much of his most significant work was published posthumously.