The developmental sequence of the types of orthographic knowledge that children acquire early in reading development is unclear. Following findings of skilled reading, the orthographic constraints of positional frequency and feedback consistency were explored with a wordlikeness judgement task for grades 1-3 English-speaking children. The data provide evidence for the early development of sensitivity to positional frequency, but not sound-spelling consistency. However, sensitivity to each type of orthographic structure was predicted by rapid naming and sensitivity to consistency was predicted by phonological awareness. As well, sensitivity to each type of constraint was related to word reading fluency.