Foster caregivers provide a family environment for hundreds of thousands of children and youth in the child welfare system in the United States (Child Welfare Information Gateway, 2016). While over half of these caregivers are in a committed couple relationship, foster caregiver couples are understudied and little is known about their experiences with fostering, especially related to their couple and coparenting relationship quality. This dissertation introduces a conceptual model to examine how contextual factors influence foster caregiver couple and coparenting relationship quality as well as other outcomes related to foster caregiving. The challenges that foster caregivers experience (e.g., increased time demands, financial strain, role ambiguity) may have a negative influence on the couple and coparenting interactions and processes between foster caregiving partners (Buehler, Cox, & Cuddeback, 2003). However, other contextual factors such as previous relationship and parenting experiences, support from formal and informal networks, and positive attitudes and perceptions may serve to counteract the negative impact of these challenges. The first study examined the associations between husbands and wives (96 dyads) perceptions of their parenting stress and couple and coparenting relationship quality. Results indicated unique actor and partner effects related to the influence of husbands and wives parenting stress on their couple and coparenting relationship outcomes. The second study examined the relationship efficacy patterns of 125 foster caregivers as well as contextual covariates (e.g., individual characteristics, family characteristics, and sources of support) using a 3-step latent profile analysis. Results indicated two unique patterns of relationship efficacy, which were associated with couple and coparenting relationship quality. Together, findings offer a better understanding of the experiences of foster caregiver couple and coparenting relationships. Findings reveal the resilience of foster caregiving couples in that they report low-to-moderate stress, moderate-to-high relationship efficacy, and high couple and coparenting relationship quality, but also suggest a need for additional resources to support foster caregiving couple and coparenting relationships.