Scientific advances in classical biological control and supporting disciplines have provided ‘tools’ that could enable permanent suppression of some seemingly intractable invasive pest problems that limit the effectiveness of Integrated Pest Management (IPM) programmes in perennial crops. This chapter examines the steps required in the development of a classical biological control programme for managing invasive insect pests. The chapter includes a detailed case study of Asian citrus psyllid, Diaphorina citri, an invasive pest of California citrus, to demonstrate the potential of ‘tools’ to support development of a classical biological control programme targeting this pest. The chapter explores the benefits of classical biological control for IPM of insect pests in perennial crops before looking ahead to future research trends in this area. The chapter provides detailed guidance on further reading on the topic.