Background and aim: Few studies have explored children’s emotional and behavioural reactions to cleft surgery and treatment-related stress. The objective was to investigate parents’ evaluations of appearance and treatment outcomes in their 5-year-old child with unilateral cleft lip and palate (UCLP), and their perceptions of how their child was coping with treatment, comparing this information with recorded postsurgical complications. Design: Three parallel group randomised clinical trials were undertaken as an international multicentre study by 10 cleft teams in five countries: Denmark, Finland, Sweden, Norway, and the UK. Methods: Three different surgical procedures for primary palatal repair were tested against a common procedure in the total cohort of 448 children born with a non-syndromic UCLP. A total of 356 parents completed the Scandcleft Parent Questionnaire, and 346 parents completed the Cleft Evaluation Profile. Results: The results indicated that the majority of parents were satisfied with cleft-related features of their child’s appearance. Further, most children coped well with treatment according to their parents. Nevertheless, 17.5% of the children showed minor or short-term reactions after treatment experiences, and 2% had major or lasting difficulties. There were no significant relationships between parent perceptions of treatment-related problems and the occurrence of post-surgical medical complications. Conclusions: Most parents reported satisfaction with their child’s appearance. However, treatment-related problems were described in some children, urging cleft centres to be aware of potential negative emotional and behavioural reactions to treatment in some young children, with a view to preventing the development of more severe treatment-related anxiety. Trial registration: ISRCTN29932826.