Narrative has been formally studied for at least two millennia, dating back to the writings of Aristotle. While most theories began by describing the construction of plotlines in theatre, most contemporary research on the structure and comprehension of narratives has examined the discourse of spoken language. However, visual narratives in the form of sequential images have also been pervasive throughout history, whether drawn on cave walls, painted on pottery, or printed in contemporary comic books and strips. Yet, compared with the study of discourse in verbal language, the study of sequential image comprehension has been relatively impoverished. Just what are the structures motivating visual narratives and how are they processed? This thesis will explore this question using experiments guided by an overall theory that sequential images at the narrative level are structured and processed analogously to sequences of words at the sentence level. The main idea is that a narrative "grammar" organizes the structure of sequential images in the visual language used in comics, similar to the way that syntax organizes words into coherent sentences. We focus here on two salient parts of this analogy. First, this thesis will explore the idea that visual narrative comprehension involves a system of narrative structure and a system of semantic coherence that contribute to comprehension. This correspondence is akin to the interaction between syntax and semantics at the sentence level. This hypothesis will be examined in an experiment in Chapter 1. Second, it explores the idea that narrative structure is a hierarchic system that organizes images into groupings of constituents, analogous to the phrase structures of syntax in sentences. This aspect of narrative structure will be explored in two experiments in Chapter 2. In conclusion, Closing Remarks will briefly discuss the overall implications for the analogy between narrative structure in sequential images and syntax in sentences. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]