Background: Pregnancy is a major event in a woman's life that is associated with conflicting emotions, joy, and anxiety. Objectives: The present study was conducted to assess the effect of Acceptance and Commitment Therapy(ACT) on women's anxiety and quality of life during pregnancy. Methods: This randomized clinical trial was conducted in 2016 on pregnant women presenting to health centers in Arak, Iran. First, eligible women were identified by referring to the health centers. Sampling was done conveniently after obtaining informed consent. Finally, 44 women were randomly allocated to ACT and control groups using two-arm blocks "A" and "B".Anxietyand quality of life were measured before the ACT, after ACT, and one month later in pregnant women using the Van den Bergh's Pregnancy-Related Anxiety Questionnaire and the 36-item Short-Form Health Survey (SF-36), respectively. The ACT group was followed up by telephone one month after the intervention. For the control group, we performed routine pregnancy care. Statistical analysis was done by the Kolmogorov-Smirnov test for normality of data distribution, followed by the chi-square test, independent t-test, and paired t-test. Results: Anxiety decreased after the intervention and increased one month later, although it was less than before intervention (P = 0.001). On the other hand, the quality of life improved after intervention, but it worsened one month later (P = 0.026). Conclusions: Counseling based on the ACT may be used for reducing anxiety in pregnant women; however, its effect on the quality of life remains to be explored further.