The present study examined gender differences in ADHD through a meta-analysis. Effect size estimates for the primary symptoms and correlates of ADHD were calculated in an attempt to replicate and extend a previous meta-analysis on gender differences in the disorder. Relatively lenient inclusion criteria were used in order to maximize the number of studies included in the effect sizes. The results indicated that in comparison to ADHD boys, ADHD girls had lower ratings on hyperactivity, inattention, impulsivity, and externalizing problems. In addition, ADHD girls had greater intellectual impairments and more internalizing problems than ADHD boys. Overall, the results of the current meta-analysis indicated general agreement with the previous meta-analysis. The clinical implications of these gender differences and future research considerations are discussed.