Task runners are tools that automate repetitive tasks in software development, making the workflow more efficient. They help developers manage tasks like minifying code, compiling stylesheets, and running tests without manual intervention. Popular task runners include Gulp and Grunt, which allow users to define tasks in a configuration file. By using task runners, developers can save time and reduce errors, as these tools execute tasks consistently. They can also integrate with other tools and frameworks, enhancing the overall development process. This automation is especially beneficial in larger projects where managing multiple tasks manually can be cumbersome.