This work aims at exploring the link between attention deficit hyperactivity disorder (ADHD) and aggressive behaviour in preschool age children. ADHD is a neurobiological disorder that is often diagnosed during childhood and is characterised by hyperactivity, impulsivity, and attention deficit. Conversely, aggressive behaviour encompasses verbal or physical actions with the sole purpose of hurting others. The research on how ADHD symptoms influence aggressive behaviour in preschool age children is done by means of study of relevant literature. This work includes an analysis of how neurobiological factors, social interactions and environments contribute to this link. Results suggest that children with ADHD are more prone to aggressive behaviour compared to their non-ADHD peers. Neurobiological factors, such as the dysfunctionality of certain parts of the brain, seem to play a significant role in this phenomenon. Furthermore, difficulties in regulating emotions and impulsivity in ADHD-children can contribute to aggressive behaviour. Social factors, such as difficulties in forming friendships or difficulties in communicating with others, also play a crucial role. Children with ADHD are often faced with bigger challenges in a social environment, which can lead to frustration and consequent aggressive reactions. Environmental factors like family dynamics and exposure to violence can further aggravate aggressive behaviour in children with ADHD. Educators play a key role in the development of children with ADHD because they are able to adapt their pedagogical approach to the individual needs of each child. Furthermore, educators need to collaborate with parents and experts to develop an individual support plan to manage ADHD symptoms and encourage the emotional development of such children. In conclusion, this work shows that there is a significant link between ADHD and aggressive behaviour in preschool age children and that neurobiological, social, and environmental factors contribute to this link. The understanding of this link is paramount for the diagnosis and presents implications for intervention that are needed to help children with ADHD and limit their aggressive behaviour.