Background: Information is available about what predicts Lidcombe Program treatment time, but nothing is known about what predicts treatment prognosis. Aims: To investigate the predictors of treatment dropout and treatment outcome for children who were treated for early stuttering with the Lidcombe Program (N = 277). Methods & Procedures: A total of 32 variables were used as predictors in regression analyses of short- and medium-term Lidcombe Program outcome, and of treatment dropout. Outcomes & Results: Regression analyses associated children who have better language skills and easy temperament with better treatment outcome, although only a small portion of the variance of treatment outcome was accounted for by these variables. There was an association between treatment dropout and parental scores on a personality screening tool relating to their impulsivity. Conclusions & Implications: Variables identified as predictors of Lidcombe Program treatment outcome were statistically significant, but not clinically significant. They did not account for a clinically substantive portion of treatment outcomes. Findings about parental impulsivity and their relationship with intervention drop-out require replication with prospective methods and comprehensive assessment of parent psychological status. This is particularly important because parents are involved in conducting all early interventions.