Kenneth Lee Pike (June 9, 1912 – December 31, 2000) was an American linguist and anthropologist. He was the originator of the theory of tagmemics, the coiner of the terms "emic" and "etic" and the developer of the constructed language Kalaba-X for use in teaching the theory and practice of translation.

In addition, he was the First President of the Bible-translating organization Summer Institute of Linguistics (SIL), with which he was associated from 1935 until his death.

Pike was born in Woodstock, Connecticut, and studied theology at Gordon College, a private Christian college in Wenham, Massachusetts, graduating with a B.A. in 1933. He initially wanted to do missionary work in China. When this was denied him, he studied linguistics with the Summer Institute of Linguistics (SIL). He went to Mexico with SIL, learning Mixtec from native speakers there in 1935.

In 1937 Pike went to the University of Michigan, where he worked for his doctorate in linguistics under Charles C. Fries. His research involved living among the Mixtecs and developing a written system for the Mixtec language with his wife, Evelyn. After receiving his Ph.D. in 1942, Pike became the First President of the Summer Institute in Linguistics. Its main function was to produce translations of the Bible in unwritten languages, and in 1951 Pike published the Mixtec New Testament. He was the President of SIL International from 1942 to 1979.

As well as and in parallel with his role at SIL, Pike spent thirty years at the University of Michigan, during which time he served as chairman of its linguistics department, professor of linguistics, and director of its English Language Institute (he did pioneering work in the field of English language learning and teaching) and was later Professor Emeritus of the university.

Pike is best known for his distinction between the emic and the etic. "Emic" (as in "phonemics") refers to the role of cultural and linguistic categories as understood from within the cultural or linguistic system that they are a part of, while "etic" (as in "phonetics") refers to the analytical study of those sounds grounded outside of the system itself. Pike argued that only native speakers are competent judges of emic descriptions, and are thus crucial in providing data for linguistic research, while investigators from outside the linguistic group apply scientific methods in the analysis of language, producing etic descriptions which are verifiable and reproducible. Pike himself carried out studies of indigenous languages in Australia, Bolivia, Ecuador, Ghana, Java, Mexico, Nepal, New Guinea, Nigeria, the Philippines, and Peru.

Pike developed his theory of tagmemics to help with the analysis of languages from Central and South America, by identifying (using both semantic and syntactic elements) strings of linguistic elements capable of playing a number of different roles.

Pike's approach to the study of language put him outside the circle of the "generative" movement begun by Noam Chomsky, a dominant linguist in the 20th century, since Pike believed that the structure of language should be studied in context, not just as single sentences, as seen in the title of his magnum opus, Language in Relation to a Unified Theory of the Structure of Human Behavior (1967).