This study qualitatively investigated the mental health of adults exposed to parental alienating behaviours in childhood. Research suggests that exposure to parental alienating behaviours in childhood can have a profound impact on the mental health of those children later in life, including experiencing anxiety disorders and trauma reactions. An international sample of 20 adults exposed to parental alienating behaviours in childhood participated in semi-structured interviews on their experience and its impact. Four themes were identified: mental health difficulties, including anxiety disorders and trauma reactions, emotional pain, addiction and substance use, and coping and resilience. Intergenerational transmission of parental alienation was found. Confusion in understanding their experience of alienation, the mental health sequelae, and elevated levels of suicidal ideation were found. This study demonstrated the insidious nature of parental alienation and parental alienating behaviours and provided further evidence of these behaviours as a form of emotional abuse.