Over the last decade, a phenomenon that has come to be known as 'algorithmic bias' has received increasing attention among those working in data science, ethics, law, and beyond. The cases to which the term is applied are, however, varied in important ways and an understanding of these variations is important for understanding whether, how, and why the phenomenon is of ethical concern. In this presentation, I discuss some of the varieties of algorithmic bias and the ethical significance that they might be thought to have.