Behavior-Driven Development (BDD) is a software development methodology that builds on Test-Driven Development (TDD) by emphasizing the alignment of software behavior with user expectations through user stories and expressive naming conventions. Introduced by Dan North in 2006, BDD employs a shared language, primarily utilizing the Given-When-Then format, to enhance communication between technical and non-technical stakeholders, thereby fostering collaboration and improving understanding of requirements. It facilitates iterative development by turning user stories into code that is validated through automated testing, using tools like Cucumber and Gherkin to ensure that applications meet expected behaviors. BDD integrates well with Agile practices and Continuous Integration/Continuous Deployment (CI/CD) workflows, offering benefits such as improved communication, enhanced requirement clarity, and increased code quality. Despite its advantages, BDD can present challenges related to collaboration, test automation, and maintaining living documentation. By focusing on user stories and leveraging automated testing, BDD helps bridge the gap between business stakeholders and developers, aligning software development with business goals and expectations.