Objective: The pathophysiological mechanisms underlying the effects of psychostimulants (methylphenidate) treatment on growth still remain controversial. We examined the long term effects of methylphenidate on height, weight and body mass index in Turkish children and adolescents with attention deficit hyperactivity disorder (ADHD). Methods: Participants (6-18 years, 330 boys, 103 girls) diagnosed with ADHD who received treatment with methyl-phenidate for at least 1 year at the Department of Child and Adolescent Psychiatry at Dokuz Eylul University Medical School were included in a retrospective study. Weight, height, and BMI z scores were converted to age- and gender- corrected z scores using norms from the Turkish population at baseline and last follow-up. Results: Height and weight standard deviation score (SDS) were reduced by treatment (baseline height-SDS [SDS]: 0.74±1.43, follow-up height-SDS [SDS]: -0.67±4.35, t-test p [Anadolu Psikiyatri Derg 2020; 21(2.000): 211-217]