Docker is not a programming language but a platform designed to make it easier to create, deploy, and run applications by using containers. However, Dockerfiles, which are used to create Docker images, are written using a simple, script-like language specific to Docker. These Dockerfiles contain commands that are executed sequentially. Even though Docker itself is not a programming language, having knowledge in certain languages like JavaScript, PHP, Node.js, Java, or Python can be beneficial when working with Docker because it helps in understanding the applications that are being containerized.