The research study aimed to assess the effectiveness of a flipped classroom strategy in enhancing the critical thinking skills of grade 12 humanities and social sciences students. Two approaches, pre-class and in-class activities were implemented with 80 students from Recto Memorial National High School. Overall, students had a positive perception of the flipped classroom strategy, and their performance in critical thinking tests was generally good. However, there were areas for improvement, particularly in inference and evaluation skills. The study found no significant difference in recognition and inferencing skills between the pre-class and in-class activities, but there was a significant difference in interpretation and evaluation skills. Recommendations were made for curriculum developers, supervisors, and administrators to enhance teaching methods through training and workshops, focusing on improving students' inference and evaluation skills. The adoption of the flipped classroom approach was encouraged, especially in social sciences, to make class discussions more engaging. Further research with a larger sample size or exploring different critical thinking subskills was suggested to provide more insight into the effectiveness of the flipped classroom approach.