Along with informatics, foreign languages are classified as one of the priority areas for development, a breakthrough in the cause of socio-economic and scientific development; Many countries have included English in their educational curricula at all levels and grades. Good English practice will bring many opportunities for everyone, especially in the current globalized context. Therefore, teaching and learning English in schools requires more positive changes. However, in addition to practical problems, many theoretical issues about innovation in teaching English at high school have not been properly and fully understood. Based on studying the legal documents of the State, inheriting the achievements of previous studies; this article continues to clarify the theoretical issues of innovation in teaching English at high school in Vietnam.