Objective: The purpose of this longitudinal study was to examine the relationship between several proposed protective factors and trauma symptoms among highly vulnerable youth in the child welfare system. Methods: Participants were 142 youth identified with a sexual behavior problem and their caregivers. Two waves of data were collected for each participant an average of 18 months apart. Foster parents reported on perceived level of support from the child welfare agency, youth involvement in club activities, and perception of youths' interpersonal and emotional competence. Youth provided self-reports of their sexual and physical abuse experiences, trauma symptoms at both time 1 and time 2, and ratings of parenting practices. Results: Youth with higher rates of sexual abuse showed more negative affect and higher levels of sexual and non-sexual rumination at time 2, controlling for time 1 scores. Boys and youth who experienced better parenting practices displayed lower negative affect. Youth with higher levels of emotional and interpersonal competence showed lower levels of non-sexual rumination. Moderation analyses revealed that youth with more significant sexual abuse histories whose foster parents did not feel supported by their child welfare caseworkers had higher levels of sexually ruminative thoughts. Finally, the results revealed that only youth without sexual abuse histories experienced the benefits of club involvement in terms of lower sexual rumination scores. Conclusions: This study demonstrated that youth with significant vulnerabilities can still exhibit a degree of protection from trauma symptomatology in the presence of a wide range of personal and social variables. These findings support the efforts of stakeholders to promote strengths at the level of the individual, family, and broader social network and community.