The focus of this thesis is the evaluation of three forms of an empirically-based cognitive-behavioural parenting program for separated families with adolescent children. However, to initially determine the existence of lasting affects of parental separation (occurring during childhood and adolescence), an exploratory study used a sample of 272 young adults (aged between 18 and 30 years) from intact families and 78 young adults from separated families. This study investigated the impact of parental marital status on young adult psychological adjustment, interpersonal relationships, attitudes toward divorce, and interpersonal behaviour problems. Results indicated that the effects of parental separation on father-child relationships persist into adulthood for men and women. Further, young women from separated families also reported more accepting attitudes toward divorce, and earlier age at entering into de facto or marital relationships. Young men reported more di fficulties in their relationships with mothers, moving out of the family home at a younger age, and higher levels of verbal attack behaviours in romantic relationships compared to their peers from intact families. Importantly, results suggested that both young children and adolescents experience adverse consequences of parental separation, albeit in different adjustment domains. Given these results, the need for intervention was established. While considerable efforts have gone into the development of intervention programs for young children from separated families, few efforts have focused on adolescents whose parents have separated. To redress this situation, this thesis describes the development and evaluation of three forms of delivery of a parenting program for separated families with adolescent children - group, individual, and telephone-assisted. Study 2 investigated the efficacy and acceptability of the Youth Adjustment to Parental Separation (YAPS) program - an empirically-based group cognitive-beha vioural parenting program for separated families with adolescent children. Overall, the results from this initial trial with four mothers suggested that the program was implemented as planned and that the program was acceptable to mothers. Further, the program lead to improvements in mothers' perceptions of adolescent symptomatology and their own symptomatology. However, there was limited or inconsistent change in mothers' perceptions of family relationships, the coparenting relationship, and their parenting practises, and in adolescents' perceptions of interparental conflict, coping, negative separation-related events, and problematic beliefs. Furthermore, adolescents reported deterioration in family communication and their own symptomatology. Based on the results of Study 2 and the limitations identified, recommendations were made regarding improvements to the YAPS program and to the procedures used to evaluate program effectiveness. According to the recommendations made in Study 2, the efficacy and acceptability of the YAPS program delivered as a therapist-administered individual program was evaluated with six families in Study 3. Results indicated that the program is acceptable to mothers, and that it leads to improvements in adolescent adjustment, parent adjustment, mother-adolescent relationships, father-contact, adolescent exposure to interparental conflict and other negative-separation-related events, and mothers' perceptions of family relationships. Less consistent changes were observed for adolescent ratings of family relationships, and the father-adolescent relationship, however improvements in the father-adolescent relationship were associated with increased levels of f ather-contact. Consistent improvements in adolescents' coping and their appraisal of parental separation were not observed. However, there appeared to be a relationship between parental utilisation of coping strategies and adolescent coping, suggesting that promoting adolescent coping indirectly through parental modelling and parental encouragement is an appropriate intervention strategy. Study 4 evaluated the efficacy and acceptability of the YAPS program delivered as a telephone-assisted program. Results indicated that the program is acceptable to mothers, and that it improves adolescent perceptions of family communication, their own coping, and their relationship with their father. However, mothers' ratings of their own and their child's adjustment, and adolescent ratings of their own adjustment did not change. Further, expected improvements in mothers' parenting practises, the mother-adolescent relationship, separation-related negative-events, separation-related beliefs, and the coparenting relationship were not observed. Overall, improvements observed in the evaluation of the minimal-contact, telephone-assisted YAPS program (Study 4) were considerably less than those observed in the evaluation of the individual therapist-assisted, face-to-face program (Study 3). Future evaluations of the YAPS program need to address the limitations of the current series of studies, particularly, comparison to a wait-list control group is required so that threats to internal validity can be minimised.