The paper begins by stipulating a definition of “standardization” that focuses on informational questions: standardizations are acts of regularization that make it easier to predict whether particular objects will be fit for particular purposes. Five case studies of various sorts from the Roman world are then considered through this lens: calibration of formal metrological apparatus; interactions between standardization and community size; use of stylized weighing apparatus; Dressel 20 amphorae and their associated labels; and Roman documentary culture. Several themes run through these case studies. The ancient Mediterranean world is characterized by strong trade-offs between intensity and scope of standardization; thus, localism is not opposed to standardization, but is an approach to it. Seemingly unproblematic levels of non-standardization in individual systems (which allow for “family resemblance”) are in danger of collapse when different systems of this sort co-exist. More attention should be directed to the real-life impact of extreme deviations from standards that scholars too often dismiss as outliers. Finally, standardizations can serve multiple purposes and (regardless of their purposes) can reinforce, avoid, or even undercut one another.