This study aimed to implement project citizen learning and analyze the effect of the project citizen learning model on students' critical thinking skills. This study utilized a quasi-experimental method through the independent sample t-test with the N-Gain Score test to determine the difference in critical thinking skills between the experimental control class and the class. Project citizen learning was implemented through six stages: problems, problem selection as discussion material, data collection, portfolio development, portfolio presentation, and learning reflection. The project citizen learning model significantly affected students' critical thinking skills in Civics subjects with a significance value of less than 0.05, namely 0.000 < 0.05. Students had changed for the better after applying the project citizen learning model.