This study aims to examine the effect of the P4C curriculum on 5-6-year-old children's critical thinking through philosophical inquiry and their problem-solving skills. The study group included a total of 40 children learning in kindergartens at an elementary school in Çanakkale, Turkey. The study used a quasi-experimental model with the pretest-posttest control group. The "Philosophy for Children Curriculum" prepared by interviewing two experts was administered to the children in the experimental group for ten weeks in two sessions per week with an average total duration of 40 minutes. The study deployed the "Critical Thinking Scale through Philosophical Inquiry for Children 5-6 Years Old" and "Problem Solving Skills Scale for Children (PSSS)" as data collection tools. The analysis results showed a significant difference between the pretest and postscores of both groups in terms of the experimental groups' critical thinking skills through philosophical inquiry within-group comparisons. Although the posttest mean score of the experimental group's critical thinking skills through philosophical inquiry was higher than the control group, no statistically significant difference was observed between them. Considering the comparisons of problem solving skills within groups, a significant difference was determined between both groups' pretest and posttest scores. When the problem solving skills were compared between groups post-test results, a significant difference was noted in favor of the experimental group.