To assess the efficacy of interarytenoid injection augmentation (IAIA) and the ability of IAIA to predict response to interarytenoid suture augmentation (IASA) based on diet advancement on video fluoroscopic swallow studies (VFSS). Retrospective cohort analysis of patients with persistent pharyngeal dysphagia at a tertiary children's hospital with VFSS pre- and post-IAIA were included between March 2011 and June 2019. Median age of the 229 patients was 2.2 years (5.8 months-19 years). Interarytenoid mucosal height (IAMH) was found to be above the false vocal folds in 112 patients (53.4%) and at true vocal folds in 10 (4.9%) patients. On VFSS post-IAIA, 95 (41.5%) patients were successfully advanced in recommended diet consistency, 115 (50.2%) were stable, and 19 (8.3%) needed thicker consistency. Paired t-tests on pre- and post-operative consistency scores showed significant improvement, p-value of <0.0001, 95% confidence interval (CI; 0.50-0.85). Poisson regression found no covariates with significant association with improvement on IAIA. For IASA patients, 35/60 (58.3%) improved on post-op VFSS. Paired t-tests on pre- and post-operative consistency scores showed significant improvement, p-value of <0.0001, 95% CI (0.63-1.33). Positive predictive value for IAIA predicting response to IASA was 77% with positive likelihood ratio of 2.3. The response to IAIA versus no response to IAIA likelihood ratios were found to have a statistically significant difference (p< 0.05). Our study suggests IAIA yields objective improvement in swallow function on VFSS in nearly half of our patients and may be a reliable diagnostic tool to predict response to IASA in patients with persistent pharyngeal dysphagia with or without a laryngeal cleft. 3 Laryngoscope, 133:1749-1756, 2023.