Gender ideology is a term used to describe a variety of issues and does not have a coherent definition. It is a protean postmodern confection that is even harder to define than most terms because it refers to a constantly changing set of claims made by its adherents. The term is often used by the anti-gender movement, which is an international movement that opposes what it refers to as "gender ideology," "gender theory," or "genderism". The anti-gender movement accuses various actors of being bearers of "gender ideology," including "liberal, green or leftist politicians, womens rights activists, LGBT activists, gender policy officers of public administrations, and gender studies scholars".

Gender ideology is the theory that the sex binary doesn’t capture the complexity of the human species, and that human individuals are properly described in terms of an “internal sense of gender” called “gender identity” that may not align with the sex assigned at birth. It is often associated with the LGBT movement and is used as a rallying cry against same-sex marriage, transgender rights, and expanding protections for sexual and gender minorities.

The term gender ideology is not equivalent to the academic discipline of gender studies, within which significant controversies and disagreements exist. The idea of gender ideology has been described by some as a moral panic or conspiracy theory, as it alleges that there is a secret cabal out to undermine society. The term is often used to attack the rights of women and LGBTI people with renewed vigor.

In summary, gender ideology is a term used to describe a constantly changing set of claims made by its adherents, which is often used by the anti-gender movement to attack the rights of women and LGBTI people. It is a protean postmodern confection that is even harder to define than most terms because it refers to a constantly changing set of claims made by its adherents.