Spelling is a key, and telling, component of children’s literacy development. An important aspect of spelling development lies in children’s sensitivity to morphological root constancy. This is the sensitivity to the fact that the spelling of roots typically remains constant across related words (e.g., sing in singing and singer). The present investigation examined the extent to which children with dyslexia and younger typically developing children are sensitive to this feature of the orthography. We did so with a spelling-level matched design (e.g., Bourassa & Treiman, 2008) and by further contrasting results with those for a sample of children of the same chronological age as the dyslexic group. Analyses revealed that the dyslexic children and their spelling-ability matched peers used the root constancy principle to a similar degree. However, neither group used this principle to its maximum extent; maximal use of root constancy did emerge for age matched peers. Overall, the findings support the idea that sensitivity to root constancy in children with dyslexia is characterized by delayed rather than atypical development.