This study investigated the effect of mastery learning and 5Es constructivist-based
instructional models on senior secondary school students’ achievement in election
contents of Government subject. The design of the study is a quasi-experimental nonequivalent group research design. The population of the study comprised 9,345 SSII
students who offer Government subject. The sample size for this study is 90 SSII
students. The instrument for data collection comprised an achievement test developed
by the researcher titled “Government Achievement Test” (GAT). The research questions
were answered using mean and standard deviation. The hypotheses were tested using
analysis of covariance (ANCOVA) at a 0.05 level of significance. The result showed that
the 5Es constructivist enhanced students’ achievement more than the mastery model
and conventional method. And that the 5Es constructivist instructional model enhanced
male and female students’ achievement more than the mastery learning model. Based
on the findings of this study it was recommended that Government teachers should
utilise 5Es constructivist-based instructional model for enhancing students’ achievement
and closing the gap between male and female students.

Keywords: Government subject, election contents, students, mastery instructional
approach, 5Es Instructional Approach