Knowledge of variables that predict treatment time is of benefit in deciding when to start treatment for early stuttering. To date, the only variable clearly related to treatment time with the Lidcombe Program is pre-treatment stuttering frequency. Previous studies have shown that children whose stuttering is more severe take longer to complete Stage 1 of the program. However, studies to date have not investigated phonology and language as predictors of treatment time. In the context of a Phase II clinical trial, the present prospective study showed that phonological development does not predict treatment time but that, together, stuttering severity, MLU and CELF Receptive Score predict 35-45% of the variance for time taken to complete Stage 1. Learning outcomes: The reader should be able to (1) understand guidelines developed for the timing of intervention with the Lidcombe Program based on previous retrospective studies, (2) determine whether pre-treatment language and phonological development play a role in treatment-led recovery with the Lidcombe Program and (3) understand recent empirical evidence on time taken by preschool children to complete Stage 1 of the Lidcombe Program.