OpenCV is an open-source computer vision library that provides tools and functions for image and video processing. It is highly optimized for real-time applications and supports multiple programming languages such as C++, Python, and Java. OpenCV offers a wide range of features including object detection, facial recognition, and image enhancement. It is cross-platform and can be used on Linux, MacOS, Windows, iOS, and Android. OpenCV is widely used in various fields such as robotics, augmented reality, and machine learning for developing applications that require computer vision capabilities.