Brain development results from the interaction between genetic and environmental factors. Childhood represents a particularly important period for neurodevelopment since the foundations of sensory and perceptual systems that are critical to cognition, emotion processing and social behaviour are formed in the early years of life and are strongly influenced by experiences during this time. Adverse childhood experiences, including those that affect children both directly (e.g. physical, emotional and sexual abuse, physical and emotional neglect) and indirectly through their environment (e.g. parental conflict, domestic violence, substance abuse, mental illness), can influence brain development in numerous ways, and these vary as a function of the presence of other risk and protective factors. The brain changes associated with adverse childhood experiences are well-documented and mainly affect areas involved in cognition, emotional processing and stress regulation. Among these, changes in the amygdala and the hippocampus have been most commonly linked to adverse childhood experiences. In addition, stressors in the first years of life seem to have a negative effect on structure and function of frontal, parietal, temporal and cingulate areas, as well as on the default mode and executive functional networks. These brain changes can then underlie the development of cognitive deficits, internalising and externalising problems, affective disorders and psychosis later in life. In this chapter, after a brief discussion on how to study the developing brain, we examine how adverse childhood experiences can affect brain development. Lastly, we discuss their relationship with psychosis as a neurodevelopmental disorder, and we highlight the main neuroimaging findings reported at the onset of this disorder.