Gaga collected awards for best international female artist, best international breakthrough act and best international album for "The Fame," and performed at the ceremony wearing a towering white wig and lace veil — complete with ornate lace eyebrows.
At points, the singer appeared overcome with emotion and paid tribute to McQueen as she collected her first prize — referring to the designer by the name Lee. "Thank you to Lee McQueen," Gaga said, her voice strained.
Gaga, a friend of McQueen, recently wore his iconic lobster-claw shoes in her "Bad Romance" music video. The designer was found dead Thursday after apparently committing suicide.
The awards are the British equivalent of the Grammys, with most winners selected by a vote of more than 1,000 industry members.
U.S. rapper Jay-Z also claimed an award, for best international male, during a ceremony at London Earl's Court arena. Other
international nominees had included Bruce Springsteen, Eminem, Jay-Z, Michael Buble and Shakira.
British boy band JLS claimed an award for best domestic breakthrough act, while recently split rockers Oasis won a one-off prize when their "(What's The Story) Morning Glory?" was named best British album of the last 30 years. Kasabian were named best British band.
Former "Take That" member and solo artist Robbie Williams received a special award for contribution to music.
Prince Harry addressed the ceremony in a recorded video message, giving the show — which has sometimes taken a raucous turn in the past — a royal stamp of approval.
Harry, third in line to the British crown, praised the awards as a celebration of "all that is totally wonderful and unique about British music."
Related Content from AccessHollywood.com:
VIEW THE PHOTOS: The Brit Awards 2009
PLAY IT NOW: Cyndi Lauper & Lady Gaga: 'The Power Is In Your Own Hands' To Prevent AIDS
PLAY IT NOW: Style Star Of The Week: Lady Gaga