Dynamic assessment is applied to phonological disorders with the Scaffolding Scale of Stimulability (SSS). The SSS comprises a 21-point hierarchical scale of cues and linguistic environments. With the SSS, clinicians assess stimulability as a diagnostic indicator and use the measure to monitor progress across treatment. Unlike other phonological measures, the SSS is sensitive to phonological change that occurs in relatively short periods of time because it measures the changes in response to cues rather than independent productions. A case study of a 3-year-old girl with phonological disorder is presented to demonstrate how the SSS documented change in stimulability after 8 weeks of treatment. Examples of changes in stimulability are presented at the phoneme, sound class, and composite levels.