Developmental transdiagnostic externalizing problems include harmful substance use, conduct problems, oppositional-defiance, and hyperactivity-impulsivity seen in Attention-Deficit/Hyperactivity Disorder (ADHD; Krueger et al., 2021). These issues have a significant societal impact, leading to high costs, including increased incarceration, delinquency, unemployment, and marital challenges (Bernfort et al., 2008, Foster and Jones, 2005). Such problems exhibit striking sex differences, with males showing higher prevalence rates (Eme, 2016, Martel, 2013). However, females with these disorders experience particularly poor outcomes compared to those without, including higher rates of somatic issues secondary to substance use, increased instances of unwanted pregnancy, and elevated rates of depression and suicide attempts, with these challenges frequently emerging during adolescence around puberty (Carroll and Anker, 2010, Becker and Hu, 2008, Chronis-Tuscano et al., 2010). In the context of ADHD, females tend to exhibit greater internalizing problems, such as depression and anxiety, compared to males, who experience greater externalizing problems, such as impulsivity and aggression. However, there is a paucity of literature examining externalizing problems in females with ADHD. Despite the substantial public health and salient individual costs specific to females with externalizing problems, they remain understudied, especially in terms of the biological and hormonal factors underlying sex differences. For these reasons, the current review will focus on externalizing problems in females rather than internalizing problems. Since this paper focuses on biological hormones, we use the terms ‘females/males’ to reflect this emphasis, and we want to clarify that this is not intended to exclude any gender identities.