Theresa Garnett (17 May 1888 – 24 May 1966) was a British suffragette. She was a serial protester who sometimes went by the name 'Annie O'Sullivan', was jailed and then still refused to cooperate. She assaulted Winston Churchill while carrying a whip. She retired from her militancy after the suffragette movement decided to commit arson as part of its protests. She was honorary editor of a women's right's magazine in 1960.