Purpose: The purpose of this study is to examine differences in phonological accuracy in multisyllabic words (MSWs) on a whole-word metric, longitudinally and cross-sectionally, for elementary school-aged children with typical development (TD) and with history of protracted phonological development (PPD). Method: Three mismatch subtotals, Lexical influence, Word Structure, and segmental Features (forming a Whole Word total), were evaluated in 3 multivariate analyses: (a) a longitudinal comparison (n = 22), at age 5 and 8 years; (b) a cross-sectional comparison of 8- to 10-year-olds (n = 12 per group) with TD and with history of PPD; and (c) a comparison of the group with history of PPD (n = 12) with a larger 5-year-old group (n = 62). Results: Significant "effect sizes" (?[subscript p][superscript 2]) found for mismatch totals were as follows: (a) moderate (Lexical, Structure) and large (Features) between ages 5 and 8 to 10 years, mismatch frequency decreasing developmentally, and (b) large between 8- to 10-year-olds with TD and with history of PPD (Structure, Features; minimal lexical influences), in favor of participants with TD. Mismatch frequencies were equivalent for 8- to 10-year-olds with history of PPD and 5-year-olds with TD. Classification accuracy in original subgroupings was 100% and 91% for 8- to 10-year-olds with TD and with history of PPD, respectively, and 86% for 5-year-olds with TD. Conclusion: Phonological accuracy in MSW production was differentiated for elementary school-aged children with TD and PPD, using a whole-word metric. To assist with the identification of children with ongoing PPD, the metric has the ability to detect weaknesses and track progress in global MSW phonological production.