Background: Both parent-report and clinician-administered autism spectrum disorder (ASD) screening instruments are important to accurately inform ASD risk ascertainment. The aim of this study was to adapt a clinician-administered ASD screening instrument, the Autistic Behavioural Indicators Instrument (ABII), as a parent questionnaire equivalent (ABII-PQ). Method: The modification of ABII items into parent questions is described. The ABII-PQ was trialled in a sample of parents of children, aged between 12 months and 6 years, with an ASD (n = 65, M child age = 4.03 years) or typical development (n = 37, M child age = 2.09 years). Results: Internal consistency was high, a = 0.92. Receiver operator curves analysis identified the optimal ABII-PQ cut-off score, which yielded high sensitivity (0.97) and specificity (0.95). Classification accuracy was high for children across the autism spectrum (autistic disorder: n = 35, 100%; Asperger syndrome: n = 14, 93%; pervasive developmental disorder not otherwise specified: n = 14, 93%). Conclusion: The ABII-PQ shows promise as a parent questionnaire version of the ABII.