Abstract Data from the National Longitudinal Survey of Children and Youth (NLSCY), and the Avon Longitudinal Study of Parents and Children (ALSPAC), both prospective cohorts, were used to explore the association between early life stressors, childhood protective factors, and early adolescent mental health outcomes (depression, anxiety, conduct disorder, and attention deficit hyperactivity disorder). Early life stressors were measured prenatally to the age of 3 within the ALSPAC analysis, while early life stressors were measured between the ages of 1-3 within the NLSCY analysis. Childhood protective factors, exclusively modifiable protective factors, (physical activity, extracurricular activities, positive parenting, and positive friendships) were measured between the ages of 6-11 within both ALSPAC and the NLSCY. Mental health outcomes were measured between the ages of 12-15 in both ALSPAC and the NLSCY. The associations between early life stressors and childhood protective factors on early adolescent mental health outcomes were computed using multivariate logistic regression modeling. It was found that the majority of early life stressors, including prenatal stressors and family dysfunction increased the odds of developing early adolescent mental health disorders although more statistically significant results were found within the NLSCY analysis. Contrarily, it was found that the majority of childhood protective factors reduced the likelihood of early adolescent mental health disorders with some exceptions found within the NLSCY analysis. No interaction terms between early life stressors and childhood protective factors were found to be statistically significant.