This study investigated the effects of Play-Based Learning (PBL) on student performance in Science and Elementary Technology (SET) and English language subjects at primary schools in Ruhango Sector, Ruhango District. The main objective of this study was to investigate the effects of play based learning on student performance of SET and English language subjects in Ruhango Sector, specifically the study focused on the effect of play based learning project, perception regarding the teacher’s roles on learner performance of SET and English language and establish the relationship between play-based learning project and learners’ performance of SET and English language subjects in primary school of Ruhango sector. The theories that guided research were Theory of Constraints (TOC) is a process designed to identify and eliminate constraints in organizational processes that hinder the achievement of organizational goals and Social Cognitive Theory is based on his central concept of self-efficacy. This study used a descriptive and correlational research designs. The target population was 150 people including headteachers and teachers. The sample size of was 96 teachers with backgrounds in SET and English language subjects and 12 headtechers. This study used questionnaire as a primary data source. The questionnaire involved written questions to which the teachers were required to write answers individually and interview guides were used to collect information from headteachers. Microsoft Office Excel was used for analyzing the results from the questionnaire and interview. The Pearson Correlation was used to test one hypothesis. The study concluded that Play Based Learning played an importance role in learner performance of Science and Elementary Technology and English language subjects through play-based activities. The research revealed a strong positive correlation between Project-Based Learning (PBL) initiatives and students' academic achievement in English language courses (r=.9650*, p=0.001). Similarly, a significant positive association was observed between Project-Based Learning (PBL) endeavours and learners' performance in Science, Elementary and Technology (SET) subjects (r=.9836*, p=0.001). The study recommends that teachers should regularly monitor content and adjust settings for individual learners. Finally, teachers should apply practices associated with engagement by determining if learner enjoy the game or want to play.