Margaret Denise Quigley, better known as Maggie Q (Vietnamese: Lý Mỹ Kỳ (Lei Mei-Kei), Chinese: 李美琪; pinyin: Lǐ Měiqí; born May 22, 1979), is a Hawaiian-born actress and former fashion model. She initially gained fame in Hong Kong.

Maggie Q was born in Honolulu, Hawaii, to an American father of Polish, French Canadian and Irish descent, and a Vietnamese mother. Her parents met while her father was stationed in Vietnam. Maggie is the youngest of five children. She has two sisters and two half-siblings from her mother's previous marriage in Vietnam. After graduating from Mililani High School, she traveled to Japan and Hong Kong to become a fashion model. In 1998, she got her first role in a Chinese-language television series.

She began acting in Hong Kong and elsewhere in East Asia. Because of her non-Chinese heritage, many of her film appearances are in English or dubbed in Chinese languages. She has, however, stated that she took Mandarin and Cantonese lessons during her career in East Asia and is able to speak both languages to varying degrees. Among her first film appearances were the lead roles in the Hong Kong action thrillers Gen-Y Cops and Naked Weapon, in which she played the martial artist assassin Charlene Ching. She has also played the titular role of Harmony in the German-Singapore telemovie collaboration Das Haus Der Harmonie, opposite leading Singaporean actress Fann Wong.

In 2006, she starred alongside Tom Cruise in Mission: Impossible III. She played Zhen, the only female member of the IMF team. In 2007, she appeared in the Bruce Willis movie Live Free or Die Hard, the fourth film in the Die Hard series, and in Balls of Fury.

In 2008, Maggie played fictional Cao Ying, a granddaughter of the warlord Cao Cao in Three Kingdoms: Resurrection of the Dragon, in her first ancient Chinese costume performance.

She also stars in the video game in the Need for Speed franchise Need for Speed: Undercover as Inspector Chase Linh who is the player's only contact to the Tri-City Police.

In 2010, it was announced that she would be the lead character on the new CW series, Nikita, a revamp of the movie/TV title.

She changed her name to Maggie Q for easier pronunciation by Chinese audiences