Over one million Syrian refugees live in Lebanon. Syrian parents are raising their children under highly stressful conditions, such as poverty, overcrowded and unsafe housing, lack of access to basic resources, and separation from loved ones, while also coping with the effects of war-related violence and loss. Chronic parental stress has been shown to negatively impact parenting among refugees and other war-affected communities, and is a key contributing factor to the intergenerational transmission of distress in communities living in adversity. Specifically, persistent parental stress and distress may lead to unresponsive, anxious, or overly harsh parenting and a corresponding increase in emotional and behaviour problems among children (Biglan et al., 2012; Cecil et al., 2012; Cummings & Davies, 1994). Traditionally, humanitarian interventions for conflict-affected children have prioritized direct work with children, while failing to address parenting and the family environment (Miller & Jordans, 2016). Recently, however, interest in parenting programs for refugees has been growing (e.g., Jordans et al., 2013; Puffer et al., 2017). However, interventions are generally based on a “deficits” framework in which problematic parenting is seen as reflecting a lack of relevant knowledge and skills. This overlooks the well-documented negative impact of chronic adversity on parent wellbeing and parenting behaviour (McLoyd, 1998, 1990). The Caregiver Support Intervention (CSI) aims to improve parental wellbeing and strengthen positive parenting in order to improve the psychosocial wellbeing of children. The CSI is a group-based, 8-session weekly intervention. It is a universal prevention program, offered to all interested parents/caregivers, rather than targeting only clinically distressed parents. It draws on evidence-based methods of stress management, emotion regulation, and positive parenting. In small-scale implementation runs in Gaza (6 groups, 30 women and 30 men) and Lebanon (3 groups, 30 women), focus group data showed good cultural fit, high participant interest and commitment (no drop outs in 9 groups, with a majority attending 7 or all 8 sessions), and good utilization of all intervention components. Participants linked the CSI and its specific components to reductions in stress, an improved capacity to cope with feelings of frustration, anger, and sadness, and improved relationships with their children and spouses. Funding is sought for two phases of work to finalize and rigorous evaluate the CSI. Phase 1: add content to the CSI to increase its relevance to parents with very young children and ensure compatibility with existing evidence-based care and theoretical frameworks; formative research on the modified intervention; and a pilot cluster RCT of the CSI to ensure all methods are well-adapted for a full pragmatic cluster RCT; Phase 2: Conduct a fully powered cluster RCT of the CSI with Syrian refugee parents/caregivers in northern Lebanon. In keeping with War Child Holland’s policy of making its interventions available to Lebanese children and families, participation in the Cluster RCT will be open to Lebanese as well as Syrian parents/caregivers. Sample size will be adequate to allow for detection of program effects among Syrian refugees specifically, and for the full sample. Specific outcomes are described below. By the end of Phase 2, a scalable caregiver support intervention will be available for use throughout War Child Holland’s global programming and in partnership with other NGOS and institutions.