The institutional grammar introduced here is based on a view that institutions are enduring regularities of human action in situations structured by rules, norms, and shared strategies, as well as by the physical world. The rules, norms, and shared strategies are constituted and reconstituted by human interaction in frequently occurring or repetitive situations. The syntax of the grammar identifies components of institutions and sorts them into three types of institutional statements: rules, norms, and shared strategies. We introduce the grammar, outline methods for operationalizing the syntax, apply the syntax to an analysis of cooperation in collective dilemma situations, and discuss the pragmatics of the grammar for analyses of behavior within complex institutional settings.