Background: Positional skull deformity usually manifests during first six months of life due to various factors like premature births or multiple births, improper positioning of infant’s head as the head of an infant is softer than the older children’s head, thus leading to either positional brachycephaly or positional plagiocephaly. Early helmet therapy intervention may improve the shape of the skull by reducing the risk of secondary cosmetic and nervous system complications. Aim: To study the effectiveness of helmet therapy in infants with positional skull deformity. Methods: The data source for this literature review is done by studying and reviewing articles through various data like Pub Med, Google Scholar, science direct, Elsevier and medicine Cochrane library. Conclusion: Helmet therapy is contemplated to be effective in the treatment of mild-moderate-severe positional skull deformity than repositioning therapy by improving the structure of the misshaped skull, as well as the use of helmet therapy is reviewed not to hinder the head circumference growth in infants.