This conceptual essay critiques current understandings of children's motivation for literacy learning, and argues for a reconceptualization of motivation that centers on the learner as agent in the social construction of meaning. The essay is illustrated with vignettes and examples drawn from two ethnographic studies conducted in whole-language classrooms. Both studies investigated children's perspectives of their own literacy learning processes and their constructs of themselves as readers and writers. The social constructivist view of intrinsic motivation offered in the essay is a holistic way of understanding cultural, interpersonal, and intrapersonal dynamics that support students' motivation for literacy learning in classrooms. Contains 53 references and a table listing elements supporting the social constructivist conceptualization of intrinsic motivation. (Author/RS)