OBJECTIVES:Parental health literacy is an important issue in paediatric chronic disease, but its role in attention deficit hyperactivity disorder (ADHD) treatment remains underexplored. This study aimed to investigate health literacy levels among parents of children diagnosed with ADHD and to evaluate the relationships between these levels, parents' decisions to accept or refuse pharmacotherapy for their children's ADHD treatment, and their children's ADHD symptoms. DESIGN:A total of 133 children with ADHD and their parents (mothers and fathers) participated in this single-centre observational study. Participants were divided into two groups: Group 1 (n = 68): parents who accepted pharmacotherapy and their children who started treatment; Group 2 (n = 65): parents who refused pharmacotherapy and their children who did not start treatment. METHODS:Parental health literacy was assessed using the European Health Literacy Survey Questionnaire (HLS-EU-Q), and ADHD children's clinical characteristics were evaluated using the Conners' Parent Rating Scale-Revised/Long (CPRS-R/L) and the Clinical Global Impression (CGI) Scale. RESULTS:Both groups had similar sociodemographic characteristics and maternal and paternal health literacy levels. In Group 1, positive correlations were found between maternal and paternal health literacy indices, as well as between CGI-I and many subscales of the CPRS-R/L (change scores = post-treatment-pre-treatment). Additionally, in Group 1, relationships were identified between maternal and paternal health literacy indices and many subscales of the CPRS-R/L (pre-treatment/post-treatment/change scores), but no relationships were found between these indices and CGI-I scores. CONCLUSIONS:These findings may suggest that assessing parental health literacy and promoting interventions to improve it could be helpful in the management of paediatric ADHD treatment.