Since IBM released the Simon Personal Communicator in 1992, smartphones have brought modernization, convenience, communication, and revolution to human society. The smartphone has become inextricable from human beings due to its fantastic features and marvelous functions. With innumerable benefits, people are addicted to smartphones without knowing it. Many researchers have examined smartphone addiction, specifically the definitions, symptoms, criteria, risk factors, and consequences of smartphone addiction in the past decades; however, the intervention strategies and the effects of intervention for smartphone addiction are scant. More research is needed to help smartphone addicts and to avoid smartphone addiction in the long run. The purpose of this chapter is to provide an overview of the definitions, symptoms, criteria, reasons, and consequences for smartphone addiction as well as to explore intervention strategies for preventing smartphone addiction. Hopefully, this chapter will contribute to digital addiction a bit and help prevent smartphone addiction.