This dissertation investigates the impact of smartphone usage on the in-store sales performance of grocery stores in the UK. It explores how consumers' reliance on smartphones for information, price comparisons, and shopping assistance influences their purchasing decisions and ultimately affects the sales of brick-and-mortar stores. The research utilizes a quantitative approach, employing a survey method to gather data from consumers who shop in-store. The study analyzes the findings to understand the relationship between smartphone usage, consumer behavior, and sales performance. The dissertation also examines the challenges and opportunities presented by the increasing integration of smartphones into the retail landscape, providing insights for retailers to adapt their strategies and leverage mobile technology to enhance customer experiences and drive sales.