Critical thinking plays a crucial role in the learning process. Critical thinking should become the focus of learning since it encourages the development of knowledge and includes the act of contemplating subjects, content, and problems. The current study aimed to investigate the effectiveness of Problem-Based Learning (PBL) and Digital Mind Maps-Integrated PBL (DMM-Integrated PBL) in improving students' critical thinking. This quasi-experiment study employed a pretest-posttest control group design, involving 103 university students from the Biology Department of University in Riau, Indonesia, as the sample. The details of each group consist of 31 students in conventional, PBL (37 students), and DMM-Integrated PBL (35 students) classes. The research data was collected using an essay test. The data obtained were analyzed using ANCOVA at a significance level of 5% and an LSD test. Essay test developed based on critical thinking indicators: basic clarification, bases for a decision, inference, advanced clarification, supposition and integration, and strategies and tactics. All the instruments had been validated. The ANCOVA analysis results proved that PBL and DMM-Integrated PBL affected the students' critical thinking. However, the LSD test showed no significant difference between PBL and DMM-Integrated PBL in promoting students' critical thinking. Finally, to promote students' critical thinking, educators are recommended to use PBL or DMM-Integrated PBL in the classroom.