The ability to perceive, comprehend and reason about relations (i.e., relational thinking) is central in human cognition. Relational thinking is powerful because it is structured. Specifically, relational thought allows inferences and generalizations that are constrained by the roles that elements play, rather than strictly the properties of the elements themselves. The role of relational comparisons in learning is emerging as an important area of developmental and learning science research. Relational comparisons allow learners to derive symbolic, abstract, and conceptual knowledge representations that are generative, in that children and adults can then use them broadly in new contexts to reason about new elements. Indeed, comparison seems to underlie the very development of the structured relational representations that underlie relational cognition. This symposium aims to bring to together research on the role of comparison in developmental and adult learning. Specifically, we present research on the role of comparison in the development of spatial reasoning, language learning, adult mathematics learning, and computational approaches to learning structured (i.e., symbolic) representations.