Glendora High School's Mission Statement serves as a foundation for improvement processes related to student learning, and reads as follows:

Glendora High School is committed to the education and development of the whole person: academically, socially, emotionally, and morally. This commitment is a shared, collaborative effort of students, support staff, teachers, parents, businesses, industry, higher education, and interested organizations. Upon graduation students will be equipped to adapt to the ever-changing world of cultural diversity, technology, employment, and society.