STEM education has been emphasized in many countries around the world because of its benefits for students in the new century. In response to STEM education, Next Generation Science Standard (NGSS) has released for a new vision of science education in which learning disciplinary content and crosscutting concepts is through engaging science and engineering practices. Educational reforms lead to a need for science teacher education programs and professional development. To prepare better for pre-service teachers, it is necessary to know their perception about these science and engineering practices. Therefore, this study aims to investigate the perception of pre-service teachers and in-service teachers’ implementation of instructional practices that align with NGSS as well as school principals’ views of science teaching. To get the goal, a convergent parallel mixed-method research design was employed in which quantitative data is a survey of science instructional practices from 187 pre-service teachers and 100 in-service teachers and qualitative data is interviews of 10 school principals in Can Tho city, Vietnam. The finding indicated that pre-service teachers highly evaluated science and engineering practices in teaching science while in-service teachers’ implementation of these practices was lower. In-service teachers tend to use more traditional instruction and incorporate students’ prior knowledge in their teaching. Although school principals revealed their appreciation toward teaching science through practices, they admitted that currently, implementation of these practices has been still limited.