Background: Researchers focused on mental health of conflict-affected children are increasingly interested in the concept of resilience. Knowledge on resilience may assist in developing interventions aimed at improving positive outcomes or reducing negative outcomes, termed promotive or protective interventions. Methods: We performed a systematic review of peer-reviewed qualitative and quantitative studies focused on resilience and mental health in children and adolescents affected by armed conflict in low- and middle-income countries. Results: Altogether 53 studies were identified: 15 qualitative and mixed methods studies and 38 quantitative, mostly cross-sectional studies focused on school-aged children and adolescents. Qualitative studies identified variation across socio-cultural settings of relevant resilience outcomes, and report contextually unique processes contributing to such outcomes. Quantitative studies focused on promotive and protective factors at different socio-ecological levels (individual, family-, peer-, school-, and community-levels). Generally, promotive and protective factors showed gender-, symptom-, and phase of conflict-specific effects on mental health outcomes. Conclusions: Although limited by its predominantly cross-sectional nature and focus on protective outcomes, this body of knowledge supports a perspective of resilience as a complex dynamic process driven by time- and context-dependent variables, rather than the balance between risk- and protective factors with known impacts on mental health. Given the complexity of findings in this population, we conclude that resilience-focused interventions will need to be highly tailored to specific contexts, rather than the application of a universal model that may be expected to have similar effects on mental health across contexts. (Contains 2 tables and 2 figures.)