Background and Objective: Women suffering from marital maladjustment face many problems in their married life, especially in psychological fields, including covert relational aggression and marital life quality. The present research was conducted with the aim of determining the effectiveness of positive mindfulness therapy on covert relational aggression and marital life quality of women suffering from marital maladjustment. Methods and Materials: This research was a semi-experimental with a pretest and posttest design with a control group. The research population were all women suffering from marital maladjustment who referred to counseling centers in the three cities of Tehran city in the autumn season of 2023 year; So that the sample size for each group was considered to be 20 people and these people after checking the inclusion criteria were selected by purposeful sampling method and randomly assigned into two equal groups. The experimental group underwent 10 sessions of 90 minutes of positive mindfulness therapy and the control group remained on the waiting list for therapy. To collect data were used from scales of covert relational aggression (Nelson and Carroll, 2006), marital quality life (Zhang et al., 2013) and marital adjustment (Spanier, 1976), and for data analysis were used from multivariate analysis of covariance in SPSS version 26 software. Findings: The results showed that positive mindfulness therapy significantly reduced the covert relational aggression and increased the marital life quality of women suffering from marital maladjustment (P<0.001). Conclusion: According to the mentioned results, therapists, counselors and psychologists can use positive mindfulness therapy to reduce the covert relational aggression and increase the marital life quality of vulnerable groups, including women suffering from marital maladjustment.