The objectives of this survey research were to: 1) study the current state of additional English course management in schools under the Secondary Educational Service Area Office Nonthaburi in Thailand; 2) study and compare the opinions of teachers and students towards the appropriateness of the current state of additional English course management; and 3) propose guidelines for the provision of additional English course management. The informants in this research included 18 heads of the foreign language learning group and 3 experts in curriculum and English language teaching. The study sample included 87 teachers and 120 high school students. The research instruments included an additional English course management form, an opinion questionnaire, and a semi-structured interview. Data analysis determining frequency, mean, standard deviation, t-test and content analysis was performed. The findings revealed: 1) overall, 60 English additional courses were offered at various schools, grouped into 5 categories according to the focus of the course, and arranged in descending order as follows: English for daily communication (33 courses), English for continuing education (10 courses), English for careers (10 courses), English for pleasure (5 courses), and others (2 courses); 2) in general, teachers and students rated each school's additional course management as appropriate at the high level and teachers and students' opinions were significantly different at the .05 level of significance; and 3) guidelines for the provision of English additional course management included support for teachers' knowledge on course development, allocation of a curriculum consultant, improvements to course management practices, and additional focus on learners' needs when developing the course.