Many philosophers have argued that alternative possibilities are required for an agent’s moral responsibility for the consequences of omitting an action. In contrast, it is argued that alternative possibilities are not required for moral responsibility for the consequences of performing an action. Thus, while an agent can be morally responsible for an action she could not have avoided, an agent is never morally responsible for omitting an action she could not have performed. Call this the Action/Omission Asymmetry Thesis. This chapter describes various strategies to challenge the Action/Omission Asymmetry Thesis and identifies the predictions those strategies make about the conditions under which an agent will be held morally responsible for an unavoidable action or omission. Studies reported in the chapter indicate that whether there is an Action/Omission Asymmetry strongly depends, first, on the type of moral judgment considered relevant for the Action/Omission Asymmetry Thesis, and, second, the scale used to test the folk’s intuition.