ThreadSanitizer is a dynamic analysis tool designed to detect data races in multi-threaded programs. It works by monitoring the execution of a program to identify unsafe interactions between threads, which can lead to unpredictable behavior and bugs. This tool is particularly useful for developers working with languages like C++ and Go, as it helps ensure that concurrent code is safe and reliable. By catching potential issues during testing, ThreadSanitizer aids in improving the overall quality and stability of software applications.