ADHD is characterized by a wide range of cognitive impairments that not only vary from childhood to adulthood but also exhibit significant inter-individual variability. Specifically, deficits in various executive functions like selective attention, cognitive flexibility, inhibition, and working memory as well as cognitive functions with low executive demand like immediate long-term and short-term memory, and sustained attention can lead to daily life challenges, which are often accompanied by impairments in decision-making. These challenges are frequently linked to neurobiological developmental aspects of ADHD, such as the effects of deficient dopamine and noradrenaline signalling pathways on affective and cognitive functions. Given the heterogeneity of the cognitive associations seen in ADHD, gaining a deeper understanding of the underlying mechanisms contributing to poor decision-making behaviour is crucial. This is particularly important because the impact of impulsivity, and diminished cognitive flexibility, on the processing of feedback on decision-making can have profound consequences for individuals with ADHD and those around them. The following chapter offers insights into the cognitive and affective functions underlying decision-making impairments in ADHD as well as the neurobiological principles associated with these challenges.