North American Computational Linguistics Open (NACLO) is a fun (and educational!) contest for U.S. and Canadian high school students in which contestants compete by solving compelling and creative puzzles in linguistics and computational linguistics. Requiring no previous knowledge of linguistics, languages, or computing, these puzzles can be solved by analytic reasoning alone, and serve as a fun introduction to a field to which many high school students have never been introduced. Winners of NACLO are eligible to compete in the International Linguistics Olympiad, one of twelve international high school science Olympiads.