Cumulative trauma, the repeated exposure to multiple traumatic events, profoundly impacts individuals’ behavioural, emotional, and social well-being. This chapter explores the biopsychosocial effects of cumulative trauma, emphasizing how chronic exposure alters brain function, disrupts relationships, and fosters maladaptive behaviours such as anxiety, depression, and aggression. Therapeutic challenges, including mistrust of providers and fragmented care, hinder the recovery process. Nursing assessments should be holistic, incorporating trauma-informed care strategies to address biological, psychological, and social needs. By understanding the complexities of cumulative trauma, healthcare providers can offer more effective, compassionate care, promoting healing and resilience.