Modern commercial broilers appear to have compromised immunocompetence, higher mortality and lower resistance to stressors. To overcome these, dietary manipulation seems to be the easiest approach, and this has been supported by research investigations conducted over the last few decades. The goal of enhancing the immune system of broilers is laudable for both economic and welfare reasons. Vitamin E (VE) is now well accepted as nature's most effective lipid-soluble, chain-breaking antioxidant. This antioxidant vitamin has been shown to improve both cell-mediated and humoral immunity in broiler chicks. However, the effect of this vitamin depends upon dose, age and genetics of the broiler chicks. Several mechanisms have been postulated for the beneficial effects of this vitamin. In this review, several aspects of the immunomodulatory effects of VE are reviewed.