This work-in-progress research paper contains the findings from a meta-analysis on the effects of using the engineering design process on K-12 students' science and mathematics achievement. This study uses a meta-analysis methodology to calculate the effect size of the integration of the engineering design process into science and mathematics teaching and learning practices on student's science and math achievements. A sample of empirical studies published during or after 2018 were included, and data were analyzed using STATA 16 statistical software. Analysis revealed a statistically significant effect size (d = 0.31 [CI= 0.18,0.44]) on students' science and mathematics achievement. The findings suggest that implementing the engineering design process enhances students' learning experiences and improves their academic achievement in science and mathematics. The results of this WIP meta-analysis should inform instructional leaders and other education stakeholders concerning the importance of integrating the engineering design process into Science, Technology, Engineering, and Mathematics teaching and learning practices.