Attention-deficit/hyperactivity disorder (ADHD) rating scales typically provide normative tables arranged according to child age, child gender, and type of informant, which facilitates addressing the fifth edition of the Diagnostic and Statistical Manual of Mental Health Disorders developmental deviance requirement for diagnosing ADHD. Missing, however, is any consideration of the gender of the informant. The purpose of this paper was to conduct an exploratory examination of informant gender via secondary analyses of a large data set used to standardize the ADHD Rating Scale-5. Two (informant gender) by two (child gender) ANOVAs were conducted separately for parents and teachers using inattention (IN) symptoms, hyperactive-impulsive (HI) symptoms, the total impairment score related to IN, and the total impairment score for HI as dependent variables. Results showed that female parents rated male children significantly higher on both IN symptoms and impairment related to IN than did male parents. Female teacher ratings were also significantly higher than male teacher ratings for male children in terms of HI symptoms and with respect to impairment ratings related to both HI and IN. A significantly higher percentage of female parents (7.7%) identified male children as being at risk for ADHD relative to male parents (4.1%). This same pattern emerged for female teachers (11.9%) versus male teachers (5.3%). Such results suggest that informant gender may play a clinically meaningful role in assessing ADHD in children and adolescents, which is consistent with the developmental literature addressing gender stereotypes in children. Future research is needed to determine whether similar informant gender differences exist in other rating scale measures of ADHD.