The use of broad theories of reading, social cognition, and social history to frame the study of literacy was investigated, and implications of this relatively recent trend were considered. Sixty-nine articles published between 1992 and 2003 in "Journal of Literacy Research/Journal of Reading Behavior", "Reading Research Quarterly", and "Research in the Teaching of English" were selected for analysis. An inventory was made of the general topic and the schools of theory used, of the specific sections of the article in which theory was cited, and of the relation between the citation of theory and previous research. From this inventory, a typology of four patterns of theory use was generated. Findings suggest that social theory matters in literacy research in at least three ways: (a) rhetorically, as support for researchers' claims; (b) as a source of new insight on the social nature of literacy and to articulate researchers' desires for a more fully literate world; and (c) for relating findings derived from local investigations to more general principles. In conclusion, it is argued that social theory is potentially a powerful tool in the production of general bodies of knowledge about literacy contingent upon increased precision, rigor, and reflexivity in its application. (Contains 4 tables.)