Humans have evolved in environments characterized by the preeminence of social dynamics. As such, the psychology of valuation—the weight we place on others’ welfare and the weight others place on our welfare in turn—has played a critical role in whether individuals have flourished or floundered over evolutionary time. While research has begun to unravel how our minds track, compute, and recalibrate such welfare tradeoffs and even how the dyadic interplay between self and others undergirds many social emotions, there is less work exploring how third- party valuation (i.e., our meta-representations of others’ valuation for a third-party) influences our psychology. In this dissertation, I present three Chapters composed of work that consider aspects of our psychology from the third-party perspective. I argue that taking such a third-party perspective sheds new light on aspects of how our minds work. In Chapter 1, I present a series of experiments (total N = 4,325) both establishing how people evaluate third-party forgivers to a transgression and offering a model to explain those evaluations. In Chapter 2, I present several experiments (N = 1,135) establishing the utility of a novel third-party criterion—a tool that compares how first and third parties feel about the success of an advantaged target—for identifying false moderators of malicious envy. And in Chapter 3, over a series of experiments (N = 1,104), I develop a competitive valuation account of envy as a system designed for competing for valuation from third parties and compare this account to more traditional accounts of envy based on personal desire. Together, these Chapters unveil the intricate dynamics of third- party valuation, illuminating novel insights into the workings of the human mind and underscoring their pivotal role in shaping interpersonal perceptions, judgments, and emotions.