The current study aimed to investigate the effectiveness of RANDAI learning model that was produced from the integration of Minangkabau culture and Problem Based Learning (PBL), in enhancing pre-service biology teachers' critical thinking skills. This experimental study used a nonequivalent pretest-posttest control group design and involved 107 pre-service biology teachers from Universitas Negeri Padang (State University of Padang), Indonesia. The data were gathered using the critical thinking essay tests. A critical thinking rubric was used to assess the participants' answers, and the results were analyzed using ANCOVA at a significance level of 0.05. The statistical results showed that RANDAI learning model affected pre-service biology teachers' critical thinking skills. The LSD test result confirmed that there was a significant difference in terms of critical thinking performance between the participants in RANDAI, Problem Based Learning, and conventional classes. Therefore, RANDAI learning model can be used to enhance the pre-service biology teachers' critical thinking skills.