The aim of this pilot study was to test the effectiveness of an educational forgiveness intervention on mental health in grieving parents. 21 grieving parents were randomly assigned to the experimental group (in which the educational forgiveness intervention occurred) and to the control group (in which a psycho-education grief intervention with a humanistic approach took place). Participants in both groups completed 12 individual hourly sessions for three months. The results showed that participants in the experimental group achieved statistically greater improvement in forgiveness towards others, self-forgiveness, and a greater decrease in depression in the post-test and follow-up test; a greater decrease in anxiety and anger in the post-test; as well as higher improvement in the post-traumatic growth in the follow-up test, four months after the end of the intervention. We highlight the potential benefits of using a forgiveness intervention with bereaved parents.