An ally is a person who is associated with another as a helper; a person or group that provides assistance and support in an ongoing effort, activity or struggle. In recent years, the term has been adopted specifically to a person supporting one or more marginalized groups. A straight ally or heterosexual ally (often simply called an ally) is a heterosexual and cisgender person who supports equal civil rights, gender equality, and LGBTQ+ social movements. Individuals may meet this designation through their actions without actively identifying as an ally.

In February 2012, American writer David M. Hall wrote an article for CNN, about the television show Glee, in which he expressed the following opinion:

The storyline on "Glee" captures something larger that we are seeing with a new generation of allies (allies are people who support LGBT rights but aren't LGBT themselves).