With respect to the importance of families and couples’ health, this study was conducted aiming at designing a commitment therapy package and assessing its effectiveness in improving couples’ marital relationship. The study was conducted following an experimental pretest-posttest-control design. The sampling population included all couples referring to psychological counseling centers in Ardabil, Iran during 2018 and 2019. Of all the couples seeking consultation from these centers, 60 available couples were selected and equally assigned to the two groups of experimental and control randomly. To conduct the study a couples’ interaction questionnaire was used both at the pretest and posttest stages. The treatment lasted for 9 sessions during each of which the couples’ underwent a treatment for two hours. The collected data were analyzed using SPSS. The internal consistency reliability of the questionnaire was estimated using Chronbach alpha and was r= .71, which falls within the acceptable range. The validity of the questionnaire was also established by expert judgment. As we know, the most important aspect of validity is whether the instrument can efficiently measure the construct it is designed to measure, that is its content validity. More specifically, content validity refers to the inclusion of skills, abilities, and qualities that are needed in measuring the behavior. The experts reviewing the package unanimously agreed that the package could measure what it was designed to measure and therefore confirmed its content validity. Likewise, to find out about the possible pretest-posttest differences and differences between the two groups, a family of t-tests was run. Results indicated that the commitment therapy package was effective in increasing the couples’ positive interactions while reducing their negative interactions in the experimental group. In other words, the package was effective in improving their marital relationship. This conclusion has many educational implications in the way of preventing and curing couples with relational problems. پرونده مقاله