This study aims to compare the presence and absence: 1) the difference in the effect of contextual learning using and without bulletins on the critical thinking ability of class X high school students on renewable energy, 2) the difference in the effect of students' curiosity between the high and low categories on the critical thinking ability of class X high school students on renewable energy, and 3) the interaction of the effect of contextual learning using and without bulletins with a level of curiosity on the critical thinking ability of class X high school students on renewable energy. The research method used is the experimental method, to determine the effect of the independent variable on the dependent variable under controlled conditions. The population of this research is class X students at Public High School 1 Wonosari in Klaten regency. The number of samples used was 64 students from 2 classes obtained using the cluster random sampling technique where the learning process for the experimental class was assisted by Contextual-Based Bulletins and the control class with PowerPoint. Data collection was obtained through curiosity questionnaires, formative assessments of critical thinking abilities, and documentation. The data obtained were analyzed using IBM SPSS Statistics and Microsoft Excel software. Data analysis by parametric statistical hypothesis test analysis of variance of two ways of unequal cell contents. The results of the research show: 1) there is a differences in the effect of contextual learning using and without bulletins on the critical thinking ability of class X high school students on renewable energy, 2) there is a difference in the effect of students' curiosity between the high and low categories on the critical thinking ability of class X high school students on renewable energy, and 3) there is an interaction between the effect of contextual learning using and without bulletins with a level of curiosity on the critical thinking ability of class X high school students on renewable energy.