Objective/Background: Determine the effects and costs of a brief behavioral sleep intervention, previously shown to improve child social-emotional functioning, sleep, and parent mental health, in a translational trial. Participants: Three hundred thirty-four school entrant children from 47 primary schools in Melbourne, Australia, with parent-reported moderate to severe behavioral sleep problems. Methods: intervention group received sleep hygiene practices and standardized behavioral strategies delivered by trained school nurses in 2013 and 2014. Control group children could receive usual community care. Results: Outcome measures: child social-emotional functioning (Pediatric Quality of Life Inventory 4.0 psychosocial health summary score-primary outcome), sleep problems (parent-reported severity, Children's Sleep Habits Questionnaire), behavior, academic function, working memory, child and parent quality of life, and parent mental health. At six months post randomization, 145 (of 168) intervention and 155 (of 166) control families completed the primary outcome for which there was no difference. Intervention compared with control children had fewer sleep problems (35.2% vs. 52.7% respectively, OR 0.5; 95% CI 0.3 to 0.8, p = 0.002) and better sleep patterns (e.g., longer sleep duration). Their parents reported fewer symptoms of depression. All differences attenuated by 12 months. There was no difference in other outcomes at either time point. Intervention costs: $AUS 182/child. Conclusions: A brief behavioral sleep intervention, delivered by school nurses to children with behavioral sleep problems, does not improve social emotional functioning. Benefits to child sleep and parent mental health are evident at 6 but not 12 months. Approaches that increase intervention dosage may improve outcomes.