<![CDATA[The purpose of this study is to determine how much the Problem-Based Learning (PBL) model's incorporation of metacognitive questions can improve students' mathematical problem-solving skills and to describe such skills after instructional implementation. A one-group pretest-posttest design was used as part of a pre-experimental strategy. The research population consisted of all seventh-grade students enrolled in SMP Negeri 17 Tasikmalaya during the 2025–2026 school year. Cluster sampling was applied in the selection of the sample, resulting in Class VII A being chosen. A mathematical problem-solving test served as the primary research instrument. Analytical procedures encompassed descriptive statistics, N-Gain computation, and effect size estimation, was carried out with IBM SPSS Statistics 24's help. The Shapiro-Wilk test was used to confirm data normality before hypothesis testing, and then a paired-sample t-test was carried out. The pretest and posttest scores after teaching that integrated metacognitive questions into the PBL framework showed a statistically significant difference, according to the results. An N-Gain percentage of 58.84% indicated a reasonably effective level of instructional influence, and the mean N-Gain value of 0.58 put the result in the moderate range. Additionally, the effect size study yielded a very big Cohen's d of 2.18. Overall, students' mathematical problem-solving proficiency upon completion of the learning activities fell within the moderate category, at a rate of 41.4%. Keywords: learning effectiveness; mathematical problem solving; metacognitive questions; PBL.]]>
