ABSTRACT Latinx adolescents face significant mental health disparities including high levels of depressive symptoms (34%), suicide ideation (14%), and attempted suicide (8%). State immigration policy climate and immigration enforcement raises serious public health concerns regarding Latinx adolescents' mental health. We explore the potential role of collective efficacy and connectedness to reduce depression and suicidal ideation related to anti-immigrant climate and immigration policy enforcement among Latinx adolescents. We propose a convergent mixed methods design with three aims: 1) Applying a difference-in-difference estimation technique within an SEM framework, and using data from the Fragile Families and Family Wellbeing Study, examine if connectedness and collective efficacy mediate the relationship of immigration policy climate and enforcement to depression and suicidal ideation, 2) Using photovoice, an YPAR method, explore adolescents' perspectives and experiences of the immigration policy climate and enforcement and its relationship to depression and suicidal ideation, and 3) we will explore adolescent perceptions and experiences of connectedness and collective efficacy in the YPAR process, using qualitative in-depth interviews with YPAR participants. These formative, qualitative data will serve to inform future development of YPAR as a potential community-level intervention that integrates strategies to build on connectedness, collective efficacy, and additional emergent social cognitive factors as targeted mechanisms of change. This mixed-method approach balances the generalizability of national estimates with contextualized adolescent perspectives to understand relevant structural factors and mechanisms that impact Latinx adolescent mental health and identify potential intervention strategies to promote mental health equity. These aims are expected to 1) Address gap in knowledge of social cognitive mechanisms that link structural environment factors and Latinx adolescent depression and suicidal ideation nationally and in context; 2) Better understanding of YPAR processes that can target social cognitive mechanisms that can be included in future interventions to reduce the burden of adolescent depression and suicidal ideation.