<![CDATA[This study aims to test and analyze the effectiveness of the Problem-Based Learning (PBL) Model in improving argumentation writing skills in elementary school students, and to determine any significant differences between the group taught using PBL and the group taught using the conventional model. The background of this study is the low ability of sixth-grade students to construct logical, evidence-supported arguments, which is suspected to be due to a lack of critical thinking stimulation in the conventional learning process. This study uses a quantitative approach with a quasi-experimental design (Quasi-Experimental Design) model of Non Equivalent Control Group Design. The subjects of the study were sixth grade students of SDN 12 Bilah Barat, Labuhanbatu Regency, Academic Year 2025-2026, which were divided into two groups, namely the Experimental Group (taught with PBL, N = 25) and the Control Group (taught with conventional models, N = 25). The instrument used was a test of argumentative text writing skills in the form of a pretest and posttest. Data were analyzed using the t-Independent Sample T-Test. The results of the prerequisite test showed that the data were normally distributed and had homogeneous variance. The results of the hypothesis test showed that the t-count of the posttest score (2.850) was greater than the t-table (2.011) with a significance value of P of 0.007 (less than 0.05). In addition, there was an increase in the average (Gain Score) in the experimental group of 1.60, much greater than the control group of 0.32. These results confirm a significant difference in argumentative writing skills between the two groups. The problem-based learning (PBL) model encourages students to identify problems, conduct investigations, and develop arguments based on evidence, which directly supports their argumentative writing skills. It is recommended that teachers implement PBL as an alternative learning model capable of stimulating students']]>
