There has been less research on how children learn to spell than on how they learn to read, but we now know a good deal about the development of spelling. In this talk, I review studies of normative development, beginning with 2-year-olds' scribbles and proceeding to prephonological spelling involving letters, invented spelling, and the more advanced spelling of primary school students. Research with learners of different languages, including English, French, and Portuguese, is presented. Theories about how children learn to spell, including constructivist theories, stage and phase theories, dual-route theories, and IMP (Integration of Multiple Patterns), are evaluated in light of the research evidence. I end the talk by considering implications of the research for instruction and assessment.