In an increasingly digital world, smartphones have become an integral part of daily life, offering convenience and connectivity. However, their pervasive usage, especially among children under the age of 5, has raised concerns regarding its impact on mental health. This study aims to explore the implications of smartphone addiction on young children and its potential effects on their mental well-being. Through a comprehensive review of existing literature, this research examines the prevalence of smartphone usage among children under 5, the factors contributing to smartphone addiction in this age group, and the potential consequences for their cognitive, social, and emotional development. The study also delves into the mechanisms through which excessive smartphone use may lead to negative mental health outcomes such as increased anxiety, reduced attention span, and disrupted sleep patterns. Furthermore, this research investigates the role of parental influence and societal norms in shaping smartphone usage patterns among young children. By analysing relevant studies and theoretical frameworks, the study highlights the importance of establishing healthy digital habits early in a child’s life and the need for effective strategies to mitigate the adverse effects of smartphone addiction.