Most young children will present at some time with problematic or challenging behaviours. However, some challenging behaviours can exceed what is considered developmentally appropriate and become established in the child’s behavioural repertoire. During a child’s preschool years, challenging behaviour is the single best predictor for later delinquency in adolescence. Without intervention, young children with challenging behaviour are at an increased risk of experiencing isolation, peer exclusion, school failure and negative effects on family. The aim of this project was to investigate the effectiveness of teaching four parent-child dyads functional behavioural assessment skills and the implementation of a function-based assessment plan with their child who engaged in challenging behaviour during the family bed-time routine time. The present project used a non-concurrent single case design with four parent-child dyads. The two, 2 hour PEP workshops were conducted at the University of Canterbury. From the two workshops, parents identified the function of their child’s challenging behaviour and identified and implemented function-based PBS strategies in the bed-time routine. Parent’s completed a 36 question Knowledge Quiz pre- and post-workshop. Video recordings and parent diary were used during baseline and post-intervention to determine the duration of the bed-time routine and the frequency of parent and child behaviours. Results showed all four parents increased their Knowledge Quiz scores by at least half of their baseline score. In terms of the duration of the bed-time routine, all four parent-child dyads decreased this routine time from a group mean of 84 to 44 minutes. The frequency of challenging behaviour also decreased from a group mean of nine to three occurrences. The parental use of positive behaviour support strategies increased for all four parents from a group mean of one to four occurrences. Results from the Social Validity Questionnaire suggest all four parents found the PEP socially acceptable and three of the four parents would recommend learning about FBA to other parents. Limitations of sample size and data collection methods are discussed. These findings provide evidence for the effectiveness of the PEP with a small group of four parents with young children.