Transgender people’s relationships have the potential to improve everyday functioning, identity, and well-being via specific pathways. While some past research has attempted to conceptualize these pathways, this work has often been theoretical rather than empirical or does not elaborate upon the specific relational experiences of transgender people (focusing on broader groups of marginalized identities instead). This thesis aimed to explore, identify, and test relational mechanisms specific to transgender people. First, potential mechanisms by which relationships influence health and well-being for transgender people are drawn from a meta-synthesis of existing literature. Second, a qualitative study composed of focus groups and interviews elucidates these mechanisms and how they are enacted through the perspective of transgender people, relational partners, and service providers. Third, concerns in imagined interactions between cisgender and transgender women are explored in order to investigate potential differences between these groups. Fourth, a diary study highlights the way in which daily relational factors contribute to positive self-image among transgender people. These studies collectively showed that positive social relationships for transgender people and their relational partners are based around concepts like gender affirmation, reciprocal coping, boosting positive self-image, and reducing the effects of stigma. However, negative relationships involved notions of identity rejection, contributing to stigma, and the forcing of gender concealment from some relational partners. These findings have implications for several domains like policy and therapeutic practice which are discussed at the end of this thesis.