Apple scab (Venturia inaequalis) is the most important apple disease worldwide. This fungus can infect both leaves and fruit under conducive conditions; tissues become increasingly resistant to V. inaequalis as they age. Although there are major resistance genes identified against V. inaequalis, nearly all commercial dessert cultivars are susceptible to V. inaequalis, thus requiring stringent control measures to minimise crop losses. This chapter introduces apple scab and explains the epidemiology of the disease, covering both host resistance and techniques of managing scab. Finally, the chapter looks ahead to future research trends on scab.