This study aimed to provide initial validity and reliability of the "Measure of NDBI Strategy Implementation-Caregiver Change" ("MONSI-CC"), a novel measure that captures changes in caregivers' implementation of NDBI strategies during early intervention. The MONSI-CC was applied to 119 observations of 43 caregiver-child dyads of preschoolers with autism spectrum disorders (ASD). The MONSI-CC showed high inter-rater and test-retest reliability and captured significant improvements in caregivers' implementation of NDBI strategies. Significant associations between improvements in caregiver NDBI implementation and improvements in the child's ASD symptoms also emerged. Our work shows promising evidence for the utility of the MONSI-CC to evaluate implementation of NDBI strategies by caregivers as a mediating and moderating factor for treatment effects on children with ASD.