The 40-year-old, born Lee Alexander McQueen, is believed to have taken his own life on the first day of New York Fashion Week. He was due to unveil his own new collection at Paris Fashion Week on March 9.
A statement from his company read: "On behalf of Lee McQueen's family, Alexander McQueen today announces the tragic news that Lee McQueen, the founder and designer of the Alexander McQueen brand, has been found dead at his home.
"At this stage it is inappropriate to comment on this tragic news beyond saying that we are devastated and are sharing a sense of shock and grief with Lee's family.
"Lee's family has asked for privacy in order to come to terms with this terrible news and we hope the media will respect this."
McQueen revealed on his Twitter feed on February 3 that his mother had passed away the day before.
He had written: "I'm letting my followers know the my mother passed away yesterday if it she had not me nor would you RIP mumxxxxxxxxxxxxxxxxxxxxxxxxxxx but life must go on!!!!!!!!!!!!!!!"
The Wall Street Journal reports that the Gucci Group has since taken down the page.
Fashion director and magazine editor Isabella Blow, who was credited with discovering McQueen, herself committed suicide by ingesting poison in May 2007.