Emily Jean Stone was born on November 6, 1988, in Scottsdale, Arizona, to Krista Jean Stone (née Yeager), a homemaker, and Jeffrey Charles Stone, the founder and CEO of a general-contracting company.
Stone lived on the grounds of the Camelback Inn resort from the age of 12 to 15.
She has a younger brother, Spencer.
Her paternal grandfather, Conrad Ostberg Sten, was from a Swedish family that anglicized their surname to "Stone" when they immigrated to the United States through Ellis Island.
She also has German, English, Scottish, and Irish ancestry.

As an infant, Stone had baby colic and cried frequently; she consequently developed nodules and calluses on her vocal cords while she was a child.
Stone has described herself as having been "loud" and "bossy" while growing up.
She was educated at Sequoya Elementary School and attended Cocopah Middle School for the sixth grade.
Although she did not like school, she has stated that her controlling nature meant that "I made sure I got all As".
Stone suffered panic attacks as a child, which she says caused a decline in her social skills.
She underwent therapy but states that it was her participation in local theater plays that helped cure the attacks.

The first time I had a panic attack I was sitting in my friend's house, and I thought the house was burning down.
I called my mom and she brought me home, and for the next three years it just would not stop.
I would go to the nurse at lunch most days and just wring my hands.
I would ask my mom to tell me exactly how the day was going to be, then ask again 30 seconds later.
I just needed to know that no one was going to die and nothing was going to change.

— Stone, The Wall Street Journal, June 2015
Stone started acting at age four; she wanted a career in sketch comedy initially, but shifted her focus toward musical theater, and took voice lessons for several years.
Her acting debut, at the age of 11, came in a stage production of The Wind in the Willows, playing the part of Otter.
The actress was homeschooled for two years, during which time she appeared in sixteen productions at Phoenix's Valley Youth Theatre—including The Princess and the Pea, Alice's Adventures in Wonderland, and Joseph and the Amazing Technicolor Dreamcoat—and performed with the theater's improvisational comedy troupe.
Around this time, she traveled to Los Angeles and auditioned unsuccessfully for a role in Nickelodeon's All That.
Her parents later sent her for private acting lessons with a local acting coach, who had worked at the William Morris Agency in the 1970s.

Stone attended Xavier College Preparatory‍—‌an all-girl Catholic high school‍—‌as a freshman, but dropped out after one semester to become an actress.
She prepared a PowerPoint presentation for her parents titled "Project Hollywood" (featuring Madonna's 2003 song "Hollywood") to convince them to let her move to California to pursue an acting career.
In January 2004, she moved with her mother to an apartment in Los Angeles.
She recalls: "I went up for every single show on the Disney Channel and auditioned to play the daughter on every single sitcom", adding, "I ended up getting none."
Between auditions for roles, she enrolled in online high-school classes, and worked part-time at a dog-treat bakery.
Emily Jean Stone was born on November 6, 1988, in Scottsdale, Arizona, to Krista Jean Stone (née Yeager), a homemaker, and Jeffrey Charles Stone, the founder and CEO of a general-contracting company. Stone lived on the grounds of the Camelback Inn resort from the age of 12 to 15. She has a younger brother, Spencer. Her paternal grandfather, Conrad Ostberg Sten, was from a Swedish family that anglicized their surname to "Stone" when they immigrated to the United States through Ellis Island. She also has German, English, Scottish, and Irish ancestry.
As an infant, Stone had baby colic and cried frequently; she consequently developed nodules and calluses on her vocal cords while she was a child. Stone has described herself as having been "loud" and "bossy" while growing up. She was educated at Sequoya Elementary School and attended Cocopah Middle School for the sixth grade. Although she did not like school, she has stated that her controlling nature meant that "I made sure I got all As". Stone suffered panic attacks as a child, which she says caused a decline in her social skills. She underwent therapy but states that it was her participation in local theater plays that helped cure the attacks.
The first time I had a panic attack I was sitting in my friend's house, and I thought the house was burning down. I called my mom and she brought me home, and for the next three years it just would not stop. I would go to the nurse at lunch most days and just wring my hands. I would ask my mom to tell me exactly how the day was going to be, then ask again 30 seconds later. I just needed to know that no one was going to die and nothing was going to change. 
— Stone, The Wall Street Journal, June 2015
Stone started acting at age four; she wanted a career in sketch comedy initially, but shifted her focus toward musical theater, and took voice lessons for several years. Her acting debut, at the age of 11, came in a stage production of The Wind in the Willows, playing the part of Otter. The actress was homeschooled for two years, during which time she appeared in sixteen productions at Phoenix's Valley Youth Theatre—including The Princess and the Pea, Alice's Adventures in Wonderland, and Joseph and the Amazing Technicolor Dreamcoat—and performed with the theater's improvisational comedy troupe. Around this time, she traveled to Los Angeles and auditioned unsuccessfully for a role in Nickelodeon's All That. Her parents later sent her for private acting lessons with a local acting coach, who had worked at the William Morris Agency in the 1970s.
Stone attended Xavier College Preparatory‍—‌an all-girl Catholic high school‍—‌as a freshman, but dropped out after one semester to become an actress. She prepared a PowerPoint presentation for her parents titled "Project Hollywood" (featuring Madonna's 2003 song "Hollywood") to convince them to let her move to California to pursue an acting career. In January 2004, she moved with her mother to an apartment in Los Angeles. She recalls: "I went up for every single show on the Disney Channel and auditioned to play the daughter on every single sitcom", adding, "I ended up getting none." Between auditions for roles, she enrolled in online high-school classes, and worked part-time at a dog-treat bakery.
Emma Stone