Abstract: We will highlight some of the manifold ways in which dark matter can be affected by cosmological phase transitions. In particular, we will discuss how a phase transition can lead to abrupt changes in the dark matter annihilation and decay rates, thereby affecting the dark matter abundance; how the dynamics of the phase transition itself can set the dark matter abundance in the context of the Filtered Dark Matter mechanism; and how phase transitions can lead to the production of primordial black holes.