Grid layouts are a design technique used in web and graphic design to create a structured and organized visual presentation. They consist of rows and columns that help align elements, making it easier for users to navigate and understand the content. By using a grid, designers can maintain consistency and balance across different screen sizes and devices. In addition to enhancing aesthetics, grid layouts improve usability by guiding the viewer's eye through the content. Popular frameworks like Bootstrap and CSS Grid provide tools for implementing grid systems, allowing designers to create responsive designs that adapt to various layouts and resolutions.