Personality disorder usually has its onset in the period between puberty and emerging adulthood (young people) and has enduring effects on education, employment, social relationships, mental and physical health, quality of life and life expectancy. Yet, diagnosis of personality disorder is often delayed and ‘late intervention’ or ‘no intervention’ is common, reinforcing therapeutic pessimism about people with personality disorder. Over the past two decades, a large body of research has provided a firm basis for establishing early diagnosis and treatment. Moreover, effective early intervention is not reliant upon availability of specialist psychotherapy. However, in order to fully realise this ambition, we must overcome discrimination from within the health professions and integrate early intervention for personality disorder with mainstream youth mental health services.