The principal aim of the researcher was to test the impact of instructional practices of teachers on students' academic performance. To achieve this aim, the researcher used a sample size of 55 teachers and 295 students in private schools in the City of Meycauayan, Bulacan during the school year 2018-2019. The primary data gathering tools used in the study was a standardized questionnaire Instructional Practices Survey adopted from Valentine (2000) on determining teachers' instructional practices and a documentary analysis from DepEd Order no.8, s. 2013 also known as the Classroom E-Record to determine the point average of the respondents' status of academic performance. The collected data were analyzed and treated statistically through the use of Statistical Packages for Social Sciences (SPSS). Results revealed that the instructional practices affect the students' academic performance in English, Mathematics, Science, Filipino, and Araling Panlipunan to a varying extent. This means that for every unit improvement in the instructional management practices mentioned could generate a certain increase in students' academic performance. The analysis of variance revealed a greater value than the significance level set at 0.05. We cannot reject the null hypothesis. We may safely conclude that the planning, teaching, and assessment practices of the teachers did not produce significant combined effects on the academic performance of students on the five content subjects in the curriculum. The study recommended that school principals may conduct frequent teachers' assessment, training needs assessment to identify the needs of teachers in terms of their profession.