Sleep disturbance is one of the main problems in post-laparotomy patients. Sleep disturbances that last a long time, can complicate the healing process and can worsen the disease. There are 2 ways to treat sleep disorders, namely pharmacological and non-pharmacological therapy. Javanese instrumental music intervention can be an alternative and effective form of intervention to overcome quality problems regardless of side effects. This study was conducted to determine the effect of Javanese instrumental music therapy on improving the sleep quality of post-laparotomy patients. This research is a quasi-experimental research. The sampling technique used in this study was purposive sampling with a sample of thirty people. The data in this study used primary data with a questionnaire. Comparing the sleep quality of the control group with the intervention group with independent t-test. Knowing the difference in sleep quality before and after the intervention of Javanese instrumental music with the paired t-test. The results showed that there were differences in the pre-test and post-test sleep quality scores with the Sig value. (2-tailed) of 0.003 for the control group and 0.001 for the intervention group. The conclusion of the study showed that there was an effect of the intervention of Javanese instrumental music on improving the sleep quality of post-laparotomy patients.