Rebbeca Marie Gomez was born on March 2, 1997 and raised in Inglewood, California. She is the daughter of Alejandra and Francisco "Frank" Gomez. All four of her grandparents are from Jalisco, Mexico, while her parents and most of her family were born in the US. Gomez has two brothers, and a younger sister. In December 2017, she revealed she has a half-sister who is eighteen years old. Gomez grew up in poverty in Moreno Valley, and at the age of nine her family lost their home and moved into the converted garage of her grandparents' house due to financial problems. Gomez began working part-time jobs to help support her family, doing commercials and voice over work. She had what she described as a "mid-life crisis" when she was nine years old, and decided she wanted to pursue a music career. She was quoted as stating "That was literally my mid-life crisis when I was nine years old. That's when I felt like, 'OK, I gotta get my life together. What am I gonna do?' I pushed that on myself at a younger age than the average kid because at the time my family had lost our home. I've always been more mature for my age, so I was already understanding what they were going through. And I just thought, 'How can I help them?'" She initially attended public school, though had to undergo home schooling due to issues with bullying. She claimed that at one point she was jumped by multiple girls while in the restroom, and was a frequent target due to her jobs in the entertainment industry.
Gomez appeared in the short film El Tux (2008) as Claudia Gómez and as Nina in the Discovery Channel television film La estación de la Calle Olvera (2008). She became a member of a girl group named G.L.A.M. in 2009, and later joined B.C.G., another girl group. She filmed a music video as part of G.L.A.M. for a song titled "JellyBean" in 2009. During this time, Gomez also began recording herself singing and rapping songs using Garageband, and created a YouTube account to post covers of popular songs online. She also began writing her own songs, and by the age of thirteen had taught herself how to play guitar. Gomez befriended production duo The Jam when she was thirteen, who liked Gomez's written work. The trio began working on material together, resulting in the covers of the songs "Otis" (2011), "Lighters" (2011), "Novacane" (2011) "Take Care" (2011), "Boyfriend" (2011), and an original song "Turn the Music Up". These songs were meant to be part of a mixtape, titled @itsbeckygomez, though this project never came to fruition. Her cover of "Otis" caught the attention of renowned Producer Dr. Luke, who had worked with artists including Britney Spears and Miley Cyrus, among others. Luke scheduled a meeting with Gomez, and asked her to play guitar for him; he later signed her to his Kemosabe Records record label, through RCA Records. In reference to her video clip for "Otis", Luke claimed "I would have signed her off that video alone. I was 100 percent in. She has so much personality and her voice just pops out of the speakers. Then I met her and discovered she could also sing and play the guitar and I thought, 'This is even better.' Then I found out she could write and it was like, 'What else are you going to tell me, that you’re also Van Gogh?' Her potential is limitless." Shortly after signing with the label, Gomez began work on her debut album.
While working on her debut album, Gomez released her first song, "Problem" featuring will.i.am, which was subsequently remixed into "Problem (The Monster Remix)" for the Sony Pictures Animation film Hotel Transylvania; the song served as a promotional single and also appeared in the movie in the end credits. Gomez and will.i.am filmed a music video for the song; it features both artists in a hotel while scenes from the movie also appear. She is featured on Cody Simpson's song "Wish U Were Here" (2012), serviced as the second single from his debut studio album. She worked with Cher Lloyd on the song "Oath" (2012), which was released as the fourth single from her debut album. The single had some commercial success, becoming Gomez's first song to chart on the Billboard Hot 100. The track was later certified gold by the Recording Industry Association of America (RIAA), denoting sales of 500,000 copies in the country. She also worked with Michel Teló on a remix of his song "Ai Se Eu Te Pego" (2012). Gomez is featured on a remix of Kesha's top ten single "Die Young" (2012) alongside Juicy J and Wiz Khalifa; the remix was featured on the Japanese deluxe edition of Kesha's second studio album, Warrior (2012).
On April 8, Gomez released "Becky from the Block" (2013) as her official debut single. The song heavily samples the Jennifer Lopez song "Jenny from the Block" (2003). Gomez filmed a music video in her neighborhood, with Lopez herself making a cameo in the clip. Entertainment Tonight described the version to have "give[n] Jenny's NY-based tune a West Coast slant". That May, Gomez released a new song, "Play It Again" (2013), for digital download. The track served as a promotional single, and was not an official single released by Gomez. On July 13, Gomez released her debut extended play, also titled Play It Again (2013). The album contained five songs on the standard edition, and its name was chosen by Gomez's fans. "Cant Get Enough" (2014), which features a guest rap from Pitbull, was serviced as the lead single from the project. The song went on to top the Latin Rhythm Airplay chart in the United States, marking her first number one single on a Billboard chart. Spanglish and Spanish versions for "Play It Again" and "Can't Get Enough" were released to digital platforms, respectively. Gomez later filmed a music video for the song "Built For This" (2013), which she directed on her own. She recorded the song "Quiero Bailar (All Through the Night)" (2013) with 3Ball MTY, which sees Gomez singing in both English and Spanish. The song was intended to be used for their second studio album.
Gomez opened for Demi Lovato and Katy Perry on select dates of their Demi and Prismatic world tours (2014–15) in both the United States and Mexico. Gomez is featured on the song "Como Tú No Hay Dos" (2015) by Mexican singer Thalía. Gomez released a song titled "Lovin So Hard" (2015), along with a music video consisting of homemade footage of Gomez and Austin Mahone, whom she briefly dated. On June 26, Gomez debuted a song titled "We Are Mexico" in solidarity with the Latin community in response to Donald Trump's remarks against illegal Mexican immigrants. She also performed at a tribute concert for the late Jenni Rivera. She released another song, "Break a Sweat" (2015), the fourth single to be released from her debut album. Gomez embarked on a co-headlining tour with Colombian reggaeton singer J Balvin beginning on September 23 and ending on October 25; the tour spanned across the United States. Gomez also released a remix with J Balvin for her single "Can't Stop Dancin". She later collaborated with Yellow Claw on the songs "Wild Mustang" and "For the Thrill" (2015). She released "You Love It" (2015) as a promotional single prior to the release of her debut album. That same day Gomez was cast as Trini in the film Power Rangers (2017). She also appeared as Valentina Galindo in two episodes of Empire adding the singles "Do It" and "New, New" (2015).
In April 2016, it was confirmed that Gomez is in a relationship with American professional soccer player Sebastian Lletget.
Gomez portrayed the Yellow Ranger, Trini, in the 2017 film Power Rangers. Her performance was received positively and made universal headlines, being the first queer superhero in a blockbuster film.