We investigated influences of non-alphanumeric rapid naming on decoding skill growth for regularly and irregularly spelled English words. In a longitudinal study, 52 at-risk and 69 not-at-risk readers were tracked from Grade 1 to Grade 3. Non-alphanumeric rapid naming ability measured in Grade 1 accounted for unique variance in irregular word decoding in early Grade 2--strong rapid naming was associated with strong irregular word decoding. An interaction between reading risk status and Grade 1 rapid naming indicated that the influence of Grade 1 rapid naming ability on growth in irregular word decoding was different for at-risk than not-at-risk readers. Non-alphanumeric rapid naming can have predictive validity as a marker for identifying specific difficulties in learning to read irregular words in at-risk readers. Results indicate that rapid naming plays a general role in irregular word reading and a specific role in at-risk readers' growth in irregular word decoding.