Purpose: The purpose of this study was twofold: (a) to gather evidence about the efficacy of performance feedback for improving school-based speech-language pathologist (SLP) narrative mediated learning implementation fidelity and (b) to determine SLPs' knowledge and attitudes about dynamic assessment (DA). Method: This investigation used a single-subject case design with baseline, intervention, and generalization phases. Participants were three elementary school SLPs who each conducted 13 DA sessions over 4 days. Data were collected on the number of mediated learning experience (MLE) procedures completed per session. The independent variable included training and performance feedback. During the intervention phase, clinicians received performance feedback using a fidelity rubric. In the generalization phase, each clinician was observed conducting three DA sessions to determine if fidelity to the rubric was maintained. Results: All three clinicians demonstrated immediate, significant improvement when performance feedback was introduced. This was evidenced by all intervention phase data points for each clinician falling outside the baseline 2-SD band. Two clinicians maintained MLE procedural fidelity with 0% nonoverlapping data between the intervention and generalization phases. Conclusions: Performance feedback using a fidelity rubric is an effective intervention for improving narrative MLE procedures and fidelity. The training, feedback, and experience gained by the participants shifted their perspectives about DA and its utility as an evaluation tool for culturally and linguistically diverse students.