This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To systematically review evidence on the effectiveness of PRT in individuals with ASD. Our specific objectives are:

• to assess the effect of PRT compared with treatment as usual or wait-list control on social communication skills in individuals with ASD based on: 1. direct observation; and 2. parent/caregiver or teacher report (or both);

• to assess the effect of PRT compared to treatment as usual or wait-list control on: 1. a. intelligence; b. restricted and repetitive behaviour; c. internalising and externalising behaviour; d. global clinical improvement; e. the dose-response of PRT; and f. possible reported adverse effects; and 2. parenting stress;

• to examine differential effects of age, gender, IQ measure before treatment, and severity of ASD symptoms on treatment outcomes; and

• to examine differential effects of fidelity of PRT implementation, duration of intervention, intensity of intervention, implementation setting and therapist involvement on treatment outcomes.