Dion and husband René Angélil in 2012
As the youngest of 14 children, Dion grew up wearing hand-me-downs and sharing a bed with several sisters. As a baby, she slept in a drawer to save on a crib. She was bullied at school and called "Vampire", owing to her teeth and skinny frame. Local tabloids even dubbed her "Canine Dion" in the teenage years of her career. She often spoke of running home from school to play music in the basement with her brothers and sisters. "I detested school", she would later write in her autobiography. "I had always lived surrounded by adults and children a lot older than me. I learned everything I needed to know from them. As far as I was concerned, real life existed around them." Dion's eldest sister was already in her 20s, married, and pregnant with her first child at the time Dion's mother, Thérèse, was pregnant with Celine.
Dion first met René Angélil, her future husband and manager, in 1980, when she was 12 and he was 38, after her brother, Michel Dondalinger Dion, had sent him a demonstration recording of "Ce n'était qu'un rêve" , a song she, her mother Thérèse, and her brother Jacques Dion had jointly written. Over subsequent years, Angélil guided her to stardom in francophone territories.
After the dissolution of Angélil's second marriage, he and Dion took a professional break and he spent the major part of the year in Las Vegas, while Dion was learning English and taking dance and singing lessons in Montreal. Upon his return, "he avoided being alone with me for too long a time", she said in her 2000 autobiography My Story, My Dream. Meanwhile, she kept a photo of Angélil under her pillow, writing, "Before I fell asleep, I slipped it under the pillow, out of fear that my mother, who always shared a room with me, would find it." She also wrote "Less and less could I hide from myself the fact that I was in love with Rene; I had all the symptoms," and "I was in love with a man I couldn't love, who didn't want me to love him, who didn't want to love me." Dion's mother, who traveled everywhere with the singer until she was 19, was initially wary of her daughter's growing infatuation with a much older and twice-divorced Angélil, but Dion was insistent, telling her mother "I'm not a minor. This is a free country. No one has the right to prevent me from loving whoever I want to."
Their professional relationship eventually turned romantic after Dion's win at the Eurovision Song Contest in Dublin in 1988; she was 20. The romance was only known to family and friends for five years, though Dion nearly revealed all in a tearful 1992 interview with journalist Lise Payette. Many years later, Payette penned the song "Je cherche l'ombre" for Dion's 2007 album D'elles.
Dion and Angélil became engaged in 1993, on Dion's 25th birthday, and made their relationship public in the liner notes of her 1993 album The Colour of My Love. They married on 17 December 1994, at Notre-Dame Basilica in Montreal, Quebec. On 5 January 2000, Dion and Angélil renewed their wedding vows in Las Vegas.
In May 2000, Dion had two small operations at a fertility clinic in New York to improve her chances of conceiving, after deciding to use in-vitro fertilization because of years of failed attempts to conceive. Their first son, René-Charles Angélil, was born on 25 January 2001. Dion suffered a miscarriage in 2009. In May 2010, Angélil announced that Dion was 14 weeks pregnant with twins after a sixth treatment of in-vitro fertilization. On Saturday, 23 October 2010, at 11:11 and 11:12 am respectively, Dion gave birth to fraternal twins by Caesarean section at St. Mary's Medical Center in West Palm Beach, Florida, The twins were named Eddy, after Dion's favourite French songwriter, Eddy Marnay, who had also produced her first five albums, and Nelson, after former South African President Nelson Mandela. She appeared with her newborn sons on the cover of 9 December 2010 issue of the Canadian edition of Hello! magazine.
On 14 January 2016, Angélil died from throat cancer. His funeral was held on 22 January 2016, in Notre-Dame Basilica in Montreal, where he and Dion wed 21 years earlier. The couple's eldest son, René-Charles, gave the eulogy just three days before his 15th birthday. Following Angélil's death, Dion became the sole owner and president of her management and production companies, including CDA Productions and Les Productions Feeling.
Two days after Angélil's death – on what would have been her husband's birthday – Dion's brother, Daniel, died at age 59, also of cancer.
On 22 March 2018, Dion's management team announced that she had been dealing with hearing irregularities for the past 12–18 months due to patulous Eustachian tube and would undergo a minimally invasive surgical procedure to correct the problem after ear-drop medications appeared to be no longer working.
Owing to her slight frame, Dion has for decades been subject of eating disorder rumors, which she has consistently denied: "I don’t have an eating problem, and there’s nothing more I can say about it". "My work requires me to be in great physical shape. I wouldn't have been able to live up to a hundred shows a year and travel ceaselessly from one end of the world to the other if I had eaten too much or not enough, or if, as certain magazines have claimed, I made myself throw up after each meal." She has often spoken about having been bullied at school and lacking confidence in her early years in the business: "I didn’t have, visually, what it took. I was not pretty, I had teeth problems, and I was very skinny. I didn’t fit the mold".
In recent years, Dion took up ballet under the guidance of her former dancer, Naomi Stikeman, who also previously performed for The National Ballet of Canada and La La La Human Steps, and former Cirque du Soleil dancer-turned-fashion-illustrator, Pepe Muñoz, who is also part of her styling team. She is also a skier and a regular at her son René-Charles' hockey games.
Dion lives in Henderson, Nevada.
Dion has expressed her love for peanut butter, claiming she loves it "so bad". Other than that, she also likes to indulge in baba ghanoush, hummus and Lebanese cuisine.