Purpose: To test the effects of a single-session parent sleep educational intervention, led by a pediatric nurse, on sleep in a group of school-aged children attending a National Health Service mental health clinic in Murcia, Spain. Design and Methods: Parents/caregivers of 26 children (mean age = 8.58 years; standard deviation = 0.58; 80.8% male) with neurodevelopmental or mental health disorders (84.6% pervasive developmental disorder), and with a suspicion of a behavioral sleep problem, participated in a 45-min group educational session about healthy sleep practices, supplemented by a written handout. The main outcome measures were derived from items of the Pediatric Sleep Questionnaire and included an insomnia composite score, a daytime sleepiness composite score, average sleep onset latency, and sleep duration on both weekdays and weekends. Outcome variables were assessed before and 3 months after the intervention. Results: After the educational intervention, the insomnia and daytime composite scores decreased significantly (ps < 0.03). Weekday and weekend sleep duration significantly increased ( ps < 0.01). No statistically significant difference was observed in sleep onset latency before and after the intervention. Practice Implications: A brief and relatively inexpensive single sleep educational session can positively impact sleep in children with neurodevelopmental and mental health disorders. Thus, this intervention meets the characteristics of a successful "entry level" treatment in a stepped-care approach. The stepped-care model places nurses in a pivotal position to ensure that their patients will receive the least complex and most accessible intervention, from which they are likely to get some benefit, and that a sizeable number of patients who need treatment may receive it. Thus, it is important for nurses in all types of practice settings to have an understanding of healthy sleep patterns, as well as sleep disorders in children. Pediatric nurses, regardless of their setting, are in a unique position to screen children and adolescents for sleep behavior problems or sleep disorders, to educate families about healthy sleep practices, provide guidance and feedback, and recommend referral to pediatric specialized care for more complex assessment and management.