The aim of this study was to investigate the relationship between motor performance, attention deficit, impulsiveness, and hyperactivity in children with attention-deficit–hyperactivity disorder (ADHD). Participants were 42 school-aged children with ADHD (36 males, 6 females; mean age 8 years 2 months, SD 1 year 2 months; range 6 years to 11 years), and 42 age- and sex-matched children without ADHD (mean age 8 years 3 months, SD 1 year 1 month; range 6 years to 11 years). Motor abilities were assessed with the Bruininks-Oseretsky Test of Motor Proficiency. Attention and impulse control were measured with the Gordon Diagnostic System, and assessment of activity level was based on two Activity Level Rating Scales that were completed by parents and teachers. Analysis by t-test revealed a significant difference between children with and without ADHD in fine and gross motor skills, impulse control, and attention. Stepwise regression indicated that attention, impulse control, and parent ratings of activity level were the three best predictors of gross motor skills for children with ADHD, accounting for 55.9% of the variance. Attention and impulse control were the two best predictors of fine motor skills, accounting for 45.7% of the variance. Attention and impulse control were consistently found to be important predictors of both fine and gross motor skills in children with ADHD. However, the fact that activity level was a predictor for gross motor proficiency but not for fine motor tasks suggests that different behavioral processes are involved in fine and gross motor performance to different extents.