Pthreads, or POSIX threads, is a standard for multi-threading in C and C++ programming. It allows developers to create and manage multiple threads within a single process, enabling concurrent execution of tasks. This can improve the performance of applications by utilizing available CPU resources more efficiently. Threads created with Pthreads share the same memory space, which facilitates communication and data sharing between them. However, this also requires careful management to avoid issues like data races and deadlocks. Pthreads provides various synchronization mechanisms, such as mutexes and condition variables, to help manage these challenges effectively.