Don Eppes is one of the two main fictional characters in the television show Numb3rs. He is played by Rob Morrow.

Don is an FBI Special Agent who recruits his mathematical genius brother, Charlie Eppes, to help him and the Bureau solve some of their most difficult cases. Don makes great sacrifices in his personal life in order to devote himself to his career, which to him is more of a way of life than a mere job. More important to him than his work is his family, especially Charlie, even though he doesn't understand his brother's way of looking at the world.

Don, along with his team, is unique in the fact that while he is focused mainly on criminal investigations, he will don SWAT gear for tactical situations as well. Don, like most of the other members of his team, carries a Glock pistol, his is a Glock 23.