Background & Aims: One of the most common chronic developmental disorders is attention deficit hyperactivity disorder, which affects about 7% of school children and 5% of adolescents and adults. Attention Deficit Hyperactivity Disorder is the most common Neuro-behavioral disorder that is seen in the clients of child and adolescent psychiatric clinics. Although in the past years, there was a false belief that this disorder improves from the years after adolescence, today the fact has become clear that this disorder will continue into adulthood in more than 50 to 75 percent of cases. The age of onset of this disorder has been determined before 5 or 7 years old. This disorder refers to people who show a level of inattention, hyperactivity, or impulsiveness and have problems at home, school, or in some social situations. Attention deficit/hyperactivity disorder is also related to learning disorder and low intelligence; many children with attention deficit hyperactivity disorder have other disorders. Emotional problems, anxiety, and depression are also seen in them. Attention-deficit/hyperactivity disorder is associated with reduced academic performance and academic progress, social exclusion, and in adults, with poorer performance, progress, and job attendance, higher probability of unemployment, and high interpersonal conflict. This disorder is noticeably disruptive in severe cases and affects social, family, and academic/occupational adaptation. Mindfulness means paying attention to specific and purposeful ways in the present and free from judgment. The conscious mind focuses on the process of continuous attention, to the content being paid attention to. Although the main goal of mindfulness is not relaxation, nonjudgmental observation of negative internal events or physiological arousal causes this state to occur. Therefore, considering the many behavioral aspects of attention deficit hyperactivity disorder can lead to mothers' depression, anxiety, and limited parental role, feelings of inadequacy and inadequacy in child rearing, weak emotional attachment between child and parent, negative relationships. These children's relationship with their brothers and sisters leads to an increase in tension in the family, a higher rate of divorce, and the breakdown of family relationships. Therefore, according to the stated content and the lack of research related to mindfulness interventions based on stress reduction in the community of parents with hyperactive-attention-deficit children, the purpose of this research is to answer the question of whether mindfulness interventions based on stress reduction is it effective on improving parent-child tension in parents of ADHD children? Methods: The current research method was quasi-experimental with a pre-test and post-test design with a control group. The statistical population of this study was made up of all mothers with children with attention-deficit/hyperactivity disorder who were referred to Mashhad psychotherapy clinics in 2016-2017. From this population, 30 mothers of children with attention-deficit/hyperactivity disorder were selected purposefully and voluntarily and were randomly replaced in the experimental group and the control group (15 people in each group). Baumrind (1972) and Barry and Jones (1995) parent stress scale questionnaire answered (pretest), then the experimental group underwent 9 sessions of mindfulness-based on Kabat and Zain (2004) stress reduction, and the control group did not receive any intervention. In the end, both groups responded to the research tools (post-test). The collected data were analyzed with spss-25 software and multivariate covariance analysis. Results: The results showed that mindfulness interventions based on stress reduction have a positive effect on parent-child tension in parents of ADHD children. Conclusion: Mindfulness techniques are effective in increasing muscle relaxation and reducing worry, stress, and anxiety. This program increases mental awareness, and well-being, and reduces stress and its physical and psychological symptoms. Time spent in formal meditative practices such as yoga is also associated with improved mindfulness and wellbeing. Therefore, mindfulness can be considered as a mediating factor for increasing psychological performance and reducing stress symptoms resulting from meditation exercises. Mindfulness based on stress reduction requires the use of special behavioral, cognitive, and metacognitive strategies to focus the attention process, which in turn prevents the downward spiral of negative mood, negative thinking, tendency to worrisome responses, and the development of perspective. It leads to new and the emergence of pleasant thoughts and emotions. Therefore, it can be concluded that mindfulness interventions based on stress reduction affect improving parenting styles and parent-child tension in parents of ADHD children. The limitations of this research include the lack of a follow-up period and the special and difficult conditions of children with attention deficit hyperactivity disorder, and it is suggested that the results of this research be used as a field for future studies in the field of knowledge of educational programs. Effective on the child's parental stress and parenting styles, parents with attention deficit hyperactivity disorder should be used. It is also suggested that the officials and those involved should plan a comprehensive treatment for these patients and their parents. [ABSTRACT FROM AUTHOR]