The abbreviation or acronym RITA (sometimes written in low case, "rita") stands for "Resistance Inside the Army", "Resister Inside the Army", or "Resist! Inside the Army".[1]

It was first invented by the American Private Richard (Dick) Perrin[2] in September 1967. It was soon widely used to describe "the resistance inside the American military" during the Vietnam War, and up to the present as a concept for similar "Resistance" movements in other armies. The term is also sometimes projected backward historically, to earlier wars when the term did not yet exist, but the phenomenon arguably already did.

Such RITA movements distinguish themselves from other components of anti-war movements, such as draft resistance or desertion, by the fact of their activists being soldiers and intending to go on being soldiers.