In this chapter, we will show you different techniques related to motion, as estimated from video frames. After a short introduction and definitions, we will show you how to read video frames captured from a camera. Then, we will tackle the all-important Optical Flow technique. In the third section, we will show you different functions that can be used for tracking. The Motion history and Background subtraction techniques are explained in the fourth and fifth sections, respectively. Finally, image alignment with the ECC method is explained. Every example has been developed and tested for the latest version of OpenCV in GitHub. Most of the functions can work in the previous versions equally, leading to some changes that will be discussed. Most of the functions introduced in this chapter are in the video module.