This dissertation explores the semantics and pragmatics of perspectival expressions. Perspective, or point-of-view, encompasses an individual’s thoughts, perceptions, and location. Many expressions in natural language have components of their meanings that shift depending on whose perspective they are evaluated against. In this dissertation, I explore two sets of questions relating to perspective sensitivity. The first set of questions relate to how perspective is encoded in the semantics of perspectival expressions. The second set of questions relate to how conversation participants treat perspectival expressions: the speaker’s selection of a perspective and the listener’s identification of the speaker’s perspective. In Part I, I explore the landscape of perspectival expressions by exploring different semantic mechanisms for encoding the perspective holder. In Chapter 2, I introduce key properties of perspectival expressions through a discussion of one canonical perspectival expression: the motion verb come. In Chapter 3, I discuss the various ways of encoding the perspective holder in the semantics of perspectival expressions. I contrast the predictions of these approaches and lay out a set of diagnostics to guide the analysis of perspectival expressions. I present two case studies using this set of diagnostics. In Chapter 3, I probe the semantics of the well-studied perspectival expression come in American English, and argue in favor of a perspective-anaphoric analysis. In Chapter 4, I focus on an expression that has not previously been recognized as perspectival, the temporal adverbial tomorrow. Through a series of experimental studies, I make the case that tomorrow is perspective-sensitive for some American English speakers, and narrow the hypothesis space for a perspectival account of tomorrow. I sketch a perspective-anaphoric semantics for tomorrow, while leaving open the possibility of a logophoric analysis. I conclude Part I with a discussion of how perspectival expressions fit into the broader landscape of context sensitivity. In Part II, I turn to a fresh set of questions about perspective: how do conversation participants select and identify perspectives? In Chapter 6, I discuss previous models of perspective production and comprehension, and factors that affect these processes, such as a bias towards the perspective of the speaker. I argue that although the selection and identification of perspective holders may be guided by simple heuristics some of the time, certain cases require a more involved reasoning system. In Chapters 7 and 8, I develop models of perspectival reasoning in comprehension and production rooted in a leading framework for pragmatic reasoning: the Rational Speech Acts framework. In Chapter 7, I propose and implement a computational model of perspective identification. I posit that listeners reason jointly about the speaker’s intended message and their adopted perspective using a mental model of the speaker’s production process. I present two comprehension studies that support a key assumption of the proposed Perspectival Rational Speech Acts model: that listeners reason simultaneously over multiple perspectives to better understand the speaker’s intended meaning. In Chapter 8, I propose a model of perspective selection that mirrors the Perspectival Rational Speech Acts comprehension model. I posit that speakers reason about the listener’s comprehension process in order to pick a perspective and an utterance that will maximize their chance of being understood. However, the results of the production study do not match the model’s predictions. I conclude with a discussion of the challenges that the attested asymmetry between speaker and listeners poses for the Rational Speech Acts framework. The main contributions of this dissertation are as follows: (1) a comparison of four approaches to encoding the semantics of perspective, leading to a diagnostic toolkit for perspectival expressions; (2) an experimental case study that employs the diagnostics to identify a novel perspectival expression; (3) an implemented computational model of perspective identification, supported by experimental evidence; and (4) an implemented computational model of perspective selection, which reveals further challenges in perspective production.