The television reality star, who was originally from Queens, New York, was found by Ryan Anderson her boyfriend unconscious. She was then rushed to a nearby hospital.
Family members took her off life support sometime Wednesday because of the critical loss to organ and brain function.
Allemand was raised in Queens and experienced heartbreak on television on The Bachelor.
Her boyfriend, who plays in the National Basketball Association, found her on Monday hanging insider her home in New Orleans.
Allemand was a former model for Maxim and after doctors determined the reality star had suffered a hug lose of organ and brain function, the family decided to remain her from life support.
A family statement said that Allemand had been surrounded by her mother, sister, boyfriend and other family and friends when she died.
No word was given by family or law enforcement authorities as to whether she had left a note prior to the hanging.
Anderson plays for the New Orleans Pelicans in the NBA and discovered her body hanging inside her home Monday and quickly called 911.
The relationship between Anderson and Allemand had recently hit a difficult patch an online Hollywood site reported.
Nevertheless, a completely distraught Anderson, who first started dating the reality star in 2011, expressed complete love for her when he spoke Wednesday.
Anderson said he was grateful for the support and love received from fans, friends and most of all family. He said Gia was more beautiful that anyone he had know both inside and out.
Over the last few days, Allemand did not give any indication she might have been depressed, which has baffled her friend and family even more.
Her last Twitter post was on Sunday and only offered a quote from Proverbs 21:3.