Providing a richer understanding of why the populations of economically underdeveloped countries are less literate than those who live in wealthier nations is the goal of this paper. Our analysis relies primarily on insights from our own research: ethnographic studies concerning literacy learning and use among unschooled and under-schooled women conducted during the late 1990s in Mexico City and historical studies of literacy in Virginia, North Carolina and Georgia along the southeastern seaboard of the USA. We examine three social mechanisms that potentially obstruct access to literacy: (1) cultural ideas and practices about schooling and written language; (2) family and personal attitudes towards literacy: (3) the impact of poverty on family life and access to literacy. Any one of these mechanisms may impede the dispersion of literacy. If all three are present, as they frequently are, then the spread and use of literacy is likely to be severely hindered. (Contains 1 note.)