Vast majority of parents continue to immunize their children against deadly infectious diseases. However, of late, growing number of them in both developed and developing nations have refused vaccination forcing the World Health Organization to declare vaccine hesitancy as one of the top ten major threats to global health. This research reviews literature published in the last few years to understand and explain the phenomenon. It identifies 10 reasons for people’s reluctance for vaccination: parental concerns, perceived disease susceptibility, parent–provider relationship, government policies, role of school authorities, weak interpersonal communication (IPC) skills of health workers, religious beliefs, role of media, social media and information on vaccines, and lack of trust. The review categorizes parents who hesitate or refuse vaccination into four categories: obedients, ditherers, doubters and defiants. Finally, it summarizes recommendations and steps that researchers and policy makers have made to stem the growing concerns regarding vaccine hesitancy.