In this study, it was aimed to investigate the effects of guided inquiry learning approach-based laboratory applications on the scientific reasoning skills of pre-service science teachers with different cognitive styles. Additionally, the opinions of pre-service science teachers with different cognitive styles about the effects of the application carried out in the study on the improvement of their scientific reasoning skills were also examined. The sample consisted of five pre-service science teachers studying at a state university in the west of Turkey. In the study, the partially mixed sequential dominant status design, which is a mixed-method research design, was used. The scientific reasoning skills of the participants were determined by using the Classroom Test of Formal Reasoning, and their cognitive styles were identified with the Group Embedded Figures Test. The opinions of the participants were taken through focus group interviews held after the application. As a result of the analysis, it was observed that the participants with field-dependent and field-intermediate cognitive styles achieved more targeted outcomes compared to those with field-independent cognitive styles. The potential relationship of this finding to the use of the guided inquiry learning approach and the hypothetico-deductive reasoning cycle during the applications was analyzed in terms of the concept of information processing, and recommendations were made for researchers. [The appendices included in this article are not numbered.]