Objective: Gender differences among children with ADHD are not well understood. The continuous performance test (CPT) is the most frequently used direct measure of inattention and impulsivity. This meta-analysis compared CPT performance between boys and girls with and without ADHD. Method: All peer-reviewed ADHD studies published between 1980 and 2010 that used a CPT and enabled gender comparison were included. Gender differences in commission (impulsivity) and omission (inattention) errors were analyzed. Results: Included studies comprised a sample of 772 boys and 325 girls with ADHD. Findings show that boys were significantly more impulsive than girls, but no difference with inattention was found. Within-gender analysis revealed that the difference among boys with and without ADHD was significantly larger than the difference among girls with and without ADHD. Conclusion: The results indicate that gender is a significant moderating factor in the assessment of core ADHD symptoms when using CPTs. (Contains 3 figures and 3 tables.)