The purpose of this research is to investigate the relationships between high school students' learning approaches and logical thinking abilities and their understandings of heat, temperature and internal energy concepts. Learning Approach Questionnaire, Test of Logical Thinking and Three-Tier Heat, Temperature and Internal Energy Test were used as data collection tools in this research. All data collection tools were administered to 120 Anatolian High School students. The data collected through these tools were analyzed using descriptive statistics and stepwise multiple regression analysis. According to the results of this research, the variable that best predicts high school students' understandings of heat, temperature and internal energy is their logical thinking abilities. Students' logical thinking abilities and their orientations toward meaningful and rote learning predict 41% of the variance of their understanding scores concerning heat, temperature and internal energy. Results of the research indicate the importance of students' logical thinking abilities and their orientations towards meaningful learning on their understandings of heat, temperature and internal energy concepts.