Testing frameworks are significant in software development as they provide structured guidelines and tools for automating the testing process. These frameworks help developers ensure that their code functions as intended by facilitating various types of testing, such as unit, integration, and regression testing. By standardizing testing practices, they help improve code quality, reduce bugs, and accelerate the development lifecycle. Furthermore, they promote collaboration and communication among team members, leading to a more cohesive development environment where issues can be identified and resolved swiftly.