Nighttime fear, including fear of monsters and the dark, is common. For most children and adolescents, nighttime fears are transient. However, approximately 10% experience severe nighttime fear that negatively impacts sleep, adjustment, and family life. Research conducted in the 1980s indicates that cognitive-behavioural therapy can reduce nighttime fear in as few as three sessions. The aims of the present study were to replicate and extend earlier research by evaluating a cognitive-behavioural treatment package for children's severe nighttime fear, and address methodological issues in previous studies. A manualised, multi-component treatment package was developed, based on current evidence-based practice for the treatment of children's anxiety. Interventions included graded exposure, muscle relaxation, cognitive restructuring, and social and material reinforcement. Treatment was individually tailored and delivered via weekly modules. A multiple baseline across-subjects design was utilised. Four ‘families’ — one parent and one child — participated; children's ages ranged from 6 to 10 years. Families attended five weekly intervention sessions and a 1-month follow-up. Multiple outcome measures were administered pre- and post-treatment. All children displayed changes consistent with reduced nighttime fear following treatment, including fewer phobic symptoms, reduced general fear, and improved nighttime and general behaviour. These changes were maintained at follow-up. Parents reported a high degree of satisfaction with the program and would recommend it to other families. The results support the effectiveness of manualised, parent-assisted treatment for nighttime fear in as few as three sessions. In cases of severe nighttime fear, therapist support is recommended. Treatment implications for children with complex presentations are discussed.