Critical thinking skills are one of the most important abilities that should be taught in math classes, however, these skills remain relatively low among some junior high school students. This study wants to find out how using the Teams Games Tournament method with a Snakes and Ladders game affects students' ability to think critically about algebra, as well as to determine the magnitude of that effect. The new idea in this study is combining the TGT model with the Snakes and Ladders game to help students develop their critical thinking skills in algebra, and the results are backed by an analysis of how effective the method is. The study used a quantitative method and followed a quasi-experimental approach with a nonequivalent control group setup. The study sample consisted of 60 seventh-grade students at Pahlawan Nasional Junior High School, comprising 30 students in the experimental class and 30 students in the control class. Data were collected using a critical thinking skills test and then analyzed through normality tests, homogeneity tests, an independent samples t-test, and Cohen’s d effect size. The t-test results showed a significance value of 0.000, which is less than 0.05, meaning there is a significant difference between the experimental group and the control group. Furthermore, the effect size analysis showed a very large effect. This result shows that using the TGT cooperative learning model with snakes and ladders as a teaching tool is good at helping students think more critically about algebra. Keywords: Teams Games Tournament (TGT), Snakes and Ladders, Critical Thinking Skills.