In a 3-year longitudinal, mixed-method study, 67 children in two schools were observed during literacy activities in Grades 1-3. Children and their teachers were interviewed each year about the children's motivation to read and write. Taking a grounded theory approach, content analysis of the child interview protocols identified the motivations that were salient to children at each grade level in each domain, looking for patterns by grade and school. Analysis of field notes, teacher interviews, and child interviews suggests that children's motivation for literacy is best understood in terms of development in specific contexts. Development in literacy skill and teachers' methods of instruction and raising motivation provided affordances and constraints for literate activity and its accompanying motivations. In particular, there was support for both the developmental hypotheses of Renninger and her colleagues (Hidi & Renninger, 2006) and of Pressick-Kilborne and Walker (2002). The positions of poor readers and the strategies they used were negotiated and developed in response to the social meanings of reading, writing, and relative literacy skill co-constructed by students and teachers in each classroom. The relationship of these findings to theories of motivation is discussed.