Benjamin Lee Whorf (/wɔːrf/; April 24, 1897 – July 26, 1941) was an American linguist and fire prevention engineer. Whorf is widely known as an advocate for the idea that because of linguistic differences in grammar and usage, speakers of different languages conceptualize and experience the world differently. This principle has frequently been called the "Sapir–Whorf hypothesis", after him and his mentor Edward Sapir, but Whorf called it the principle of linguistic relativity, because he saw the idea as having implications similar to Einstein's principle of physical relativity.

Throughout his life Whorf was a chemical engineer by profession, but as a young man he took up an interest in linguistics. At first this interest drew him to the study of Biblical Hebrew, but he quickly went on to study the indigenous languages of Mesoamerica on his own. Professional scholars were impressed by his work and in 1930 he received a grant to study the Nahuatl language in Mexico; on his return home he presented several influential papers on the language at linguistics conferences. This led him to begin studying linguistics with Edward Sapir at Yale University while still maintaining his day job at the Hartford Fire Insurance Company. During his time at Yale he worked on the description of the Hopi language, and the historical linguistics of the Uto-Aztecan languages, publishing many influential papers in professional journals. He was chosen as the substitute for Sapir during his medical leave in 1938. Whorf taught his seminar on "Problems of American Indian Linguistics". In addition to his well known work on linguistic relativity, he wrote a grammar sketch of Hopi and studies of Nahuatl dialects, proposed a deciphering of Maya hieroglyphic writing, and published the first attempt towards a reconstruction of Uto-Aztecan.