`std::lock_guard` is a C++ utility that helps manage mutexes, which are used to protect shared data from being accessed by multiple threads simultaneously. When a `std::lock_guard` object is created, it automatically locks the specified mutex, ensuring that no other thread can access the protected resource until the lock is released. This helps prevent race conditions and makes multithreaded programming safer and easier. When the `std::lock_guard` object goes out of scope, it automatically unlocks the mutex, which simplifies resource management. This automatic locking and unlocking mechanism reduces the risk of forgetting to release a lock, making code more robust and less error-prone. Using `std::lock_guard` is a best practice for managing mutexes in C++ applications.