The objective of this research was to examine the implementation of Problem-Based Learning (PBL) in improving grammatical correctness in English writing among first-year elementary teacher candidates at Pakse Teacher Training College. Employing a pre-experimental research design, data were collected using pre-test and post-test grammar writing assessments alongside student feedback questionnaires. The quantitative analysis indicated a statistically significant improvement in post-test scores following the PBL intervention. The collaborative and context-driven nature of PBL enabled students to apply grammatical rules more accurately in contextualized tasks, demonstrating the effectiveness of active learning methodologies in English language teacher education.