Güngör and Şanal Güngör, 2026

This mixed-methods randomized controlled study examined the effectiveness of an Acceptance and Commitment Therapy–based psychoeducational program for divorced noncustodial fathers (ACT-DNF) in enhancing psychological flexibility and reducing parenting stress. Fifty-two fathers were randomly assigned to either the ACT-DNF or an active psychoeducation control group. Quantitative data were collected at pretest, posttest, and two follow-ups, while qualitative interviews were conducted with 15 experimental participants. Repeated-measures ANOVAs revealed significant group × time effects across all flexibility dimensions (ηp2 = .28–.36) and in parenting stress (ηp2 = .35), with improvements maintained through both follow-ups. Increases in psychological flexibility were strongly associated with decreases in stress (r = –.61, p < .001). Thematic analysis identified four processes—acceptance, emotion regulation, value-based parenting, and cooperative co-parenting—illustrating how ACT mechanisms were applied in daily fathering. Findings indicate that a brief, group-based ACT program can effectively enhance psychological flexibility and alleviate parenting stress among divorced noncustodial fathers, providing an evidence-based model for post-divorce family interventions.