Background: Nonword repetition (NWR) is a common phonological processing task that is reported to tap into many cognitive, perceptual, and motor processes. For this reason, NWR is often used in assessment batteries to aid in verifying the presence of a reading or language disorder. Aims: To examine the extent to which child- and item-level factors predict the probability of a correct response on a non-word repetition (NWR) task in a sample of children with persistent speech sound disorders (P-SSDs) compared with their typically developing peers. Methods & Procedures: A total of 40 American-English-speaking children were tested on an NWR task for which the stimuli were manipulated for phonological neighbourhood density and list length. Additional measures of vocabulary and word reading were also administered. Outcomes & Results: Children who were typically developing were 1.82 times more likely than children with P-SSD to respond correctly. The item-level factor of phonological neighbourhood density influenced performance, but only for the P-SSD group, and only at certain list lengths. Vocabulary and word-reading ability also influenced NWR task performance. Conclusions & Implications: Children with P-SSD present as a complex and heterogeneous group. Multiple factors contribute to their ability to perform phonological tasks such as NWR. As such, attention to the item-level factors in screenings and assessments is necessary to ensure that appropriate decisions are made regarding diagnosis and subsequent treatment.