Currently critical thinking skills is becoming an important education issue to overcome the challanges of industrial revolution 4.0. Previous studies reported that the pre-service teachers' critical thinking dispositions and skills were still low, therefore, both aspects of critical thinking should be improved through learning activities in higher education. This study aimed to determine the effectiveness of the online critical thinking cycle learning model to improve pre-service science teachers' critical thinking disposition and critical thinking skills. This study used pre-experimental research with one group pretest-posttest design. The online critical thinking cycle learning model was implemented in two classes without a control group. A total of 58 preservice science teachers from two different universities participated in this study. Each pre-service teacher's critical thinking dispositions and skills were measured using the critical thinking disposition inventory and critical thinking skills test. The results showed that the pre-service science teachers' critical thinking disposition and critical thinking skills increased after the implementation of the online critical thinking cycle learning model with a g score of 0.697 and 0.712, respectively. There was no significant difference in the pretest and post-test scores, and there was a consistent increase in g score between the two classes studied. Thus, the online critical thinking cycle learning model is effective and consistent to improve pre-service science teachers' critical thinking dispositions and skills.