Poor sleep quality is one of the most common complaints in pregnancy, which can lead to adverse maternal and fetal outcomes. Therefore, counseling with pregnant women to use non-pharmacological methods such as music therapy appears to be helpful. The aim of this study was to assess the effectiveness of music therapy counseling on sleep quality in pregnancy. This quasi-experimental study was conducted among 88 pregnant women, which were allocated randomly into two forty four-member groups of intervention and control in Hamadan city, Iran, 2015. The questionnaire used in this study was Pittsburgh Sleep Quality Index (PSQI). Two counseling sessions for using music therapy were held for experimental group. They were asked to listen to a calm music CD for 4 weeks, every night for 45 minutes. Then both groups were evaluated after 4 weeks. Data were analyzed with SPSS 16, by using chi-square, paired t-test and independent t-test. Data analysis showed that no significant differences had been found in component's scores of sleep quality in the control group before and after the intervention(P˃0.05) except the fifth component; the fifth component score significantly increased (P=0.03). In the experimental group, there was a significant decrease in component scores of sleep quality (except fifth component) and total sleep quality score after the intervention. But the fifth component did not change significantly after the intervention. Also the comparison of the two groups by using Independent t-test showed a statistically significant difference between the total sleep quality score, first component (subjective sleep quality), second component (sleep latency), and seventh component (daily function disorder) after intervention between two groups (P˂0.001). Counseling with pregnant women to use music therapy can have an effective role in improving their sleep quality in pregnancy.