In recent days, security is a big threat in the transmission medium due to the development of the Internet and multimedia contents such as audio, image, video etc. For transmitting secret images, security issues should be taken into consideration because hackers may utilize weak link over communication network to steal information that they want. Video Steganography is the process of hiding some secret information inside a video. The addition of this information to the video is not recognizable by the human eye as the change of a pixel colour is negligible. In this paper, a review on various video steganography techniques has been presented.