Background: Unforgiveness refers to the prolonged unwillingness to forgive perceived wrongdoings, which can significantly affect mental and physical well-being. In contrast, resentment or grudges involve holding onto past grievances. This study examined gender differences in experiences and expressions of unforgiveness to address existing knowledge gaps. 
Methods: In this qualitative research, 34 university students (19 men and 15 women) were recruited from Sagar, Madhya Pradesh, India via purposive and snowball sampling in 2022. Purposive sampling targets specific characteristics, while snowball sampling recruits similar participants. Both yield relevant data for thematic analysis but limit generalizability due to smaller, specific samples. Participants shared their unforgivable experiences in semi-structured interviews developed from previous studies on unforgiveness. The transcriptions were analyzed thematically. 
Results: The participants’ mean age was 26.43±2.88 years. The themes of similarities and differences in unforgiveness reflect both shared and distinct experiences. Both genders reported feelings of hurt, revenge, and anger, with unforgiveness manifesting as avoidance and neglect. This suggests a common emotional and behavioral response, emphasizing the role of unforgiveness in personal growth and protection from future harm. However, gender-specific differences emerged in the nature of transgressions: men reported bullying and humiliation, while women emphasized cheating and sexual abuse. Additionally, men viewed unforgiveness as a tool for offender reform, whereas women saw it as a means of protection. 
Conclusion: Understanding gender differences in unforgiveness can guide gender-specific interventions, addressing men’s emphasis on reform and women’s protective motives. Further research should explore cultural influences on unforgiveness and test the effectiveness of tailored therapeutic interventions across diverse populations.