Introduction: Women's happiness represents a vital role in the performance and health of the family. The present study aimed to investigate the mediating role of difficulties in cognitive emotion regulation in the relationship between interpersonal forgiveness and social intelligence with happiness in female-headed households. Method: The study was a cross-sectional study that included 261 female-headed households, which were selected by the convenience sampling method. The research instrument included the Oxford Happiness Inventory (OHI), Tromsø Social Intelligence Scale (TSIS), Interpersonal Forgiveness Measurement Questionnaire (IFMQ) and Difficulties in Emotion Regulation Scale (DERS). Analysis of the data involved both descriptive and inferential statistics including mean, standard deviation, Pearson's correlation, and path analysis. Results: A significant, direct, and positive relationship was observed between social intelligence and happiness. The relationship between difficulties in cognitive emotion regulation with happiness was significant, direct, and negative. There was no direct and significant relationship between interpersonal forgiveness and happiness. Difficulties in cognitive emotion regulation had a mediating role in the relationship between social intelligence and interpersonal forgiveness with happiness. Conclusion: The results of this study indicated the importance of the mediating role of difficulties in cognitive emotion regulation in the relationship between social intelligence, interpersonal forgiveness, and happiness.