Geometric flows have proved to be a powerful geometric analysis tool, perhaps most notably in the study of 3-manifold topology, the differentiable sphere theorem and Kähler metrics. In the context of $G_2$ geometry, there are several geometric flows which arise. Each flow provides a potential means to study the geometry and topology associated with a given class of $G_2$ structures. I will introduce these flows, and describe some of the key known results and open problems in the field.