Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 17 1 2022 01 01 61 71 Ghazal Davodi-Boroujerd Department of Clinical Psychology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Imaneh Abasi Department of Clinical Psychology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Abbas Masjedi Arani Department of Clinical Psychology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Maryam Aslzaker Department of Clinical Psychology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2020 05 27 Objective: Although many studies have investigated the effect of maternal personality on internalizing and externalizing behaviors of a child, the role of both mother and child’s emotional mechanisms in these behaviors is little explored. The present study was focused on the relationship between the mother’s personality, and internalizing and externalizing behaviors of children with the mediating role of children’s alexithymia, mother’s alexithymia, and children’s emotion regulation (ER). Method: 162 mothers and elementary school-aged children were recruited regarding their demographics and completed the NEO personality inventory, Child behavior checklist, Toronto alexithymia scale, Children’s alexithymia measure, and Children’s emotion regulation checklist. Data were analyzed using SPSS (ver.23), and AMOS (ver.23). Results: Structural equations modeling demonstrated an acceptable model fit to data (CMIN/DF = 1.233, RSME = 0.038, GFI = 0.962). Mother’s alexithymia predicted internalizing problems whereas it didn’t predict externalizing problems in children. Also, the bootstrap results indicated that the mother and children’s alexithymia and children’s ER had mediating roles between mother’s personality and externalizing and internalizing problems. Conclusion: The present results demonstrated that mother’s personality can indirectly, through mother and children’s alexithymia and children’s ER act as an important factor in development of mental problems. In other words, findings indicated that children’s emotional development is not a one-way road, but it is a mutual process that involves both the mother and the child. https://ijps.tums.ac.ir/index.php/ijps/article/view/2190 https://ijps.tums.ac.ir/index.php/ijps/article/download/2190/1036