Implementation of The Bandongan Method to Improve Student Learning Outcomes on Acid-Base Material]The purpose of this research was to determine the increase in learning outcomes of acid-base material after students take part in learning that is subject to the implementation of the bandongan learning method. It is known that the understanding and learning outcomes of students on acid-base material have not been maximized due to the passiveness and low interest of the student in participating in chemistry lessons. One solution that teachers can do to overcome this is to implement the right method in learning. The learning method chosen in this research is one of the methods that characterize Islamic boarding school learning, namely the bandongan method. The bandongan method was chosen by considering that MAN 3 Kediri is a madrasah school and the majority of the student's backgrounds are santri. This research is categorized in the type of pre-experimental research with research subjects namely students of class XI MIPA 4 for the academic year 2021/2022 at MAN 3 Kediri. This research uses instruments in the form of pretest and posttest sheets. The increase in students' acid-base learning outcomes is indicated by research data in the form of an average n-gain score of 0.61 which includes the medium criteria. This shows that the bandongan method can improve students' acid-base learning outcomes.