K–12 (pronounced just "kay twelve", or "kay through twelve", "kay to twelve") is a designation for the sum of primary and secondary education. It is used in the United States, Canada, and some parts of Australia.

The expression is a shortening of Kindergarten (5 or 6-year-old) through 12th grade (or grade 12) (generally 17 or 18-year-old), the first and last grades of free education in the United States, Australia and English Canada.

By contrast, K–14 education also includes community colleges (first two years of university) and K–16 education adds a four-year undergraduate university degree.