This study aims to improve students' conceptual understanding through the application of mindful, meaningful, and joyful learning in science learning for fourth graders at SD Negeri 214/IV, Jambi City. This study used the Classroom Action Research (CAR) method with all 28 fourth grade students as subjects. The research process was carried out cyclically, including the planning stage, action implementation, observation, and reflection. Data collection techniques included observation, conceptual understanding tests, interviews, documentation, and field notes. Data analysis was carried out qualitatively through reduction, presentation, and drawing conclusions, and quantitatively by comparing test results in each cycle. The results showed that before the action, learning was still dominated by lectures so that students were passive and conceptual understanding was low. After the application of mindful, meaningful, and joyful learning through the Think-Pair-Share model, there was a significant increase. Student activity increased by 82.14%, and the average value of the conceptual understanding test increased from 58.21% to 78.57% with 78.57% of students completing. Interviews and observations showed that students were more active, focused, brave in asking questions, and able to relate the material to everyday experiences. The application of these three approaches fosters conscious, meaningful, and enjoyable learning, thus encouraging student engagement and better conceptual understanding. This study recommends more intensive guidance for passive students, optimization of learning media, and effective management of discussion time to improve overall learning completion.