Zinc (Zn) is an essential nutrient for plants as well as animals. It is required for diverse critical plant physiological and metabolic processes, for instance, photosynthesis, chlorophyll synthesis, carbohydrate metabolism, and starch and sucrose synthesis. Zinc plays a key role in gene expression and regulation, protein synthesis, nitrogen fixation, and plant defense against numerous biotic and abiotic stressors. Even though the food availability has increased, its nutritional characteristics have decreased. In this context, the significance of micronutrients, including Zn, in dietary food has become a subject of universal interest having health-related issues. There are several important animal and human physiological processes involving Zn. Zn deficiency leads to loss of several millions of dollars every year in the form of additional medical expenses and claims lives of millions of people, mostly affecting kids. It is believed that around 17% of the human population on earth are facing the threat of Zn deficiency. Zinc deficit is linked to difficulty in pregnancy, under-developed growth, early deaths, immune system impairment, and several neurobehavioral ailments in human beings. The present chapter highlights the significance of Zn in several metabolic processes of plants and animals (including humans) in order to understand the problem of Zn paucity with respect to its influence on crop growing and human well-being, taking into account the available literature.