This research aimed to determine the effectiveness of the Inquiry Social Complexity (ISC) learning model to improve critical and creative thinking skills of senior high school students in Indonesia. The research method used was experimental with pre-test-post-test group design. The research sample were 32 students using the ISC model and 30 students using Discovery Learning in the acid-base material. The data were analysed using the ANCOVA test resulting in F = 79.381 with a significance level of 0.000 (p < 0.05), meaning that there were significant differences between using the ISC model and using the Discovery Learning. There was a gap of 39.66% between the pre-test and post-test results of the experimental class and 24.83% of the control class. It can be concluded that learning process using ISC learning model is very effective to improve students' critical and creative thinking skills.