This chapter describes current psychological research on graph comprehension. We describe current models of graph comprehension, including both detailed computational and mathematical models as well as general process models. In the next sections, we describe the influence of display characteristics (e.g., line graph vs. bar graph, color vs. black and white), data complexity, and task on graph interpretation. Finally, we describe the effect of individual differences and developmental factors. Specifically, we consider how graphical literacy skills, content knowledge, visuospatial abilities, and working memory influence the interpretation of graphs. Finally, we discuss practical implications of this review and provide directions for future research.