Aim: The aim of this study was to compare the effectiveness of Bowenian family therapy and acceptance and commitment therapy on the difficulty in regulating the emotion of mothers with one child. Methods: This was a descriptive quasi-experimental study with a pretest-posttest design with two experimental groups and a control group. The statistical population of the study included all mothers with only one child of preschool age in Kermanshah kindergartens in 2019. A total of 45 people were selected through convenience sampling and 15 people were randomly assigned to two experimental groups and one control group. Data were collected in the pretest-posttest stages with a scale of difficulty in emotion regulation (Grotz and Roemer, 2004). After pre-testing, members of the two experimental groups participated separately in eight 1.5-hour weekly sessions of Bowenian family therapy and acceptance and commitment therapy. Analysis of covariance and Bonferroni post-hoc test were used to analyze the data. Results: The results of analysis of covariance showed that the effect of Bowenian family therapy and the effect of acceptance and commitment based therapy on difficulty in emotion regulation in individuals is significant (P<0.05). Also, differences in the two treatment groups for the dimensions of emotional rejection, difficulty in performing behavior, difficulty in controlling impulse, lack of emotional awareness, limited access, and lack of clarity, respectively, the amount of F statistic; 4.771, 4.461, 3.524, 3.399 and 5.720 with significant levels were 0.026, 0.005, 0.011, 0.001, 0.003 and 0.009, respectively. The results of Bowenian test showed that due to the size of the differences, the effectiveness of acceptance-based and commitment-based therapy in combining with other interventions on the difficulty of emotion regulation and its related components was higher (P <0.05). Conclusion: Psychologists, when faced with problems of mother-child interaction, evaluate the mother in terms of the level of cognitive emotion regulation and other psychological variables affecting emotion regulation and use effective treatment methods if there is a problem.