Integration of teaching is described as the systematic arrangement of knowledge in teaching to combine or unify matters of subject isolated in the academic curriculum. The purpose of this study is to investigate Vietnamese teachers, principals, and vice-principals in secondary schools' awareness and the implementation of integrated teaching in Natural Science subjects in secondary schools, Hoc Mon District, Ho Chi Minh City, Vietnam. Participants completed survey questionnaires about the awareness about objectives for fostering quality integrated teaching, the objectives’ importance in integrated teaching, and the implementation of integrated teaching of Natural Science subjects. The results revealed that the integrated teaching in integrated teaching of Natural Science subjects was highly trained and well-implemented by secondary school teachers. The educational curriculum assists students in discovering, investigating comprehensive solutions, and examining various aspects of problems.