The current research is aimed at investigating the relations between forgiveness, vengeance, perceptions of parental acceptance-rejection, and psychological adjustment in 528 Kuwaiti males and females (mean age =30.92, and SD= 7.72 years) by using Arabic versions of the following four measures and questionnaires 1) The Heartland Scale, 2) The Vengeance Scale, 3)The Acceptance-Rejection Questionnaire (PARQ), and 4) The Personality Assessment Questionnaire (PAQ). The data was analyzed using descriptive and inferential statistical analysis. Results revealed that forgiveness correlated significantly negative with vengeance, and significantly positive with both the perceptions of parental acceptance and healthier psychological adjustment. Vengeance correlated significantly positive with perception of parental rejection and unhealthier psychological adjustment. No significant differences were found between males and females in perception of mother warmth. Males, compared with females, were significantly higher in perceiving maternal and paternal rejection. Females, compared with males, perceived their fathers as having more warmth, Older and married participants reported significantly higher levels of healthier adjustment and forgiveness, compared with younger and unmarried participants. Males and younger participants reported significantly higher levels of vengeance, compared with females and older participants. Significant influence of education or work on the perception of parental acceptance-rejection, psychological adjustment, forgiveness No and vengeance, was found. A Multiple Mediator Model "MMM" showed that forgiveness and vengeance fully mediated and moderated the relation between perceptions of parental acceptance-rejection and psychological adjustment. Moreover, the M. M. M. analysis showed that perceptions of parental acceptance-rejection and psychological adjustment were effective predictors of the relationship between forgiveness and vengeance. Limitations of the study were considered and the significance of the results is discussed. In consideration of results, some suggestions were made for the implementation and for further research.