Psychometrically sound tests of intellectual ability are indispensable for research and assessment of children with autism spectrum disorder (ASD), yet few tests have been validated for use with this population. The Merrill–Palmer–Revised Scales of Development (M-P-R) is a standardized test of intellectual ability that was validated for use with typically developing preschoolers. The current study’s aim was to investigate the criterion validity of the M-P-R for assessing cognitive skills in preschoolers with ASD ( N = 180). Good concurrent validity was demonstrated, with a large positive correlation between the M-P-R Receptive Language domain and the PLS-4 Auditory Comprehension subscale. The Cognitive domain of the M-P-R showed a medium positive correlation with later WISC-4 scores, showing acceptable predictive validity. Cognitive strengths and weaknesses assessed using the M-P-R mirrored those described for other measures, with most children obtaining higher standard scores on the Cognitive than the Receptive Language domain. An exploratory factor analysis suggested that one factor accounted for the majority of variability in M-P-R domains.