While both light and sound travel as waves, the speed of light is much, much faster.
Light is composed of electromagnetic waves which travel independent of a medium.
That is to say, light can travel in a vacuum, such as outer space. Electromagnetic waves travel very fast. However, when light passes through transparent materials, it slows down a bit. This is because electromagnetic waves interact with the subatomic components of matter. In water, for example, light slows down to around 0.75c, or 225,000,000 meters per second.