Competing theories are quite common in education. In spelling research, two general perspectives have emerged over the years: stage theory and repertoire/alternative theories. Exploring these perspectives is important because teachers need to understand how spelling knowledge is critical for learning to read words and to write them. Stage theory suggests that learners follow a developmental progression that reflects the increasing complexity of the spelling system itself. Alternative theorists suggest that learners do not follow a linear progression but are able to understand much more information about the spelling system throughout their development. The author explores the debate between these two conceptions, identifying not only important differences but also where there is common ground. Implications for spelling, word analysis, and vocabulary instruction are provided.