The TestNG DataProvider feature allows users to pass parameters into a test method, enabling the reuse of code and reduction in testing time. By using a DataProvider, testers can create multiple test cases from a single test method, reducing redundancy and improving test efficiency. This feature is particularly useful for scenarios with large numbers of permutations and combinations to test. The TestNG DataProvider can be used to pass strings or more complex parameters into a test method, allowing users to iterate over different data sets without having to write separate code for each scenario. Additionally, the DataProvider can be used in conjunction with other features such as parallel execution and reporting to further improve testing efficiency.