An English-medium education system is one that uses English as the primary medium of instruction—particularly where English is not the mother tongue of the students.

Initially this is associated with the expansion of English from its homeland in England and the lowlands of Scotland and its spread to the rest of Great Britain and Ireland, beginning in the sixteenth century. The rise of the British Empire increased the language's spread to British colonies and in many of these it has remained the medium of education. The increased economic and cultural influence of the United States since World War II has also furthered the global spread of English, as has the rapid spread of Internet and other technologies. As a result of this, in many states throughout the world where English is not the predominant language there are English-medium schools. Also in higher education, due to the recent trend towards internationalization, an increasing number of degree courses, particularly at Master's level, are being taught through the medium of English.

Known as English-Medium Instruction (EMI), or ICLHE (Integrating Content and Language in Higher Education), this rapidly growing phenomenon has been contested in many contexts.