This project develops and tests a theory, the Theory of Argumentative Norms. The Theory of Argumentative Norms states that individuals carry specific social norms into interpersonal arguments that depend on the goal of the argument—persuasion, inquiry, identity, or play. Conforming to these norms is theorized to lead to optimal argumentative perceptions and outcomes, and violating any of these norms is thus theorized to lead to more negative consequences. The first two chapters detail the theory and its specific normative constructs, leading to the construction of ten hypotheses and a research question. The nature of the theory called for the creation of new instruments and stimuli, so the next two chapters detail the piloting of these measures and materials. The predictions are then tested in two further studies, primarily by the construction and manipulation of dialogic argument vignettes that do or do not contain particular violations, and then asking participants to rate the vignettes for their conformity to argument norms and for other argumentative perception and outcome measures. Findings of the research were mostly supportive of the theory: it was found that norm violations were associated with significantly more negative perceptions than normative arguments, both with respect to in-the-moment perceptions (argument quality, pleasantness) and outcomes (goal attainment, future willingness to argue, escalation). The theory also predicted that different argument goals would be associated with different patterns of outcomes, but these predictions were mostly unsupported.