Close relationships are vital to human flourishing. The Social Connection and Positive Psychology Lab at Arizona State University investigates how and why close relationships are related to happiness and well-being. Along with our students and collaborators, we investigate how specific relationship promoting behaviors, such as gratitude and kindness, lead to increases in happiness. In addition, we explore how and why becoming a parent is related to to changes--both positive and negative--in well-being. We investigate these topics with a variety of methods, including randomized controlled interventions, longitudinal studies, daily experience studies, and cross-sectional surveys of nationally representative samples.