Lazaan-Malinao Elementary School in Nagcarlan Sub-Office has long recognized the importance of formative assessment in enhancing learning outcomes. However, many teachers struggled to implement effective assessment strategies as learners found it difficult to comprehend and respond to higher-order thinking questions, limiting their engagement and critical reasoning. This challenge highlighted the need to strengthen teacher competence and support systems to make classroom assessments more meaningful and responsive to learner needs. To address this, the study implemented Project QUEST – Questioning for Enhanced Student Thinking, which aimed to improve teachers’ formative assessment practices through technical assistance, professional development, and access to instructional resources. Employing a descriptive-experimental design, the research involved twelve (12) teachers and pupils from Grades I to VI. Data were collected through validated questionnaires, focus group discussions, and comparative analysis of students’ pre-test and post-test Mean Percentage Scores (MPS). Findings revealed that the teachers’ level of formative assessment practice improved from a “Satisfactory” mean of 2.99 before the intervention to a “Very Satisfactory” mean of 4.22 after its implementation. Correspondingly, the overall student MPS increased from 61.87% to 77.18%, showing a gain of 15.31%. The computed t-value of 8.52, exceeding the critical value at 0.05 significance level, confirmed a statistically significant improvement in student performance. The study concludes that sustained teacher support—through mentoring, professional learning communities, and adequate instructional resources—enhances formative assessment literacy and student achievement. It recommends the institutionalization of continuous capacity-building programs, data-driven instruction, and formative assessment integration in the School Improvement Plan (SIP) to sustain instructional quality and promote deeper, more reflective learning among pupils.