The huge turnout easily surpassed the previous record, set in Moscow in 2017 when 3,000 people showed up for boxing class.
A huge gathering is seen during the biggest ever boxing class in Mexico City.
Mexico City has set a world record for hosting the largest boxing class ever, with 14,299 people taking part in a massive lesson in the capital's central plaza. Photos from the event went viral on social media and showed the participants dressed in green, white, and red t-shirts that represented the colours of the Mexican flag.
The 30-minute class on Saturday was taught by 15 popular Mexican boxers, including world champions Mariana "Barby" Juarez.
The huge turnout easily surpassed the previous record, set in Moscow in 2017 when 3,000 people showed up for boxing class. A Guinness World Records team certified the attendance figure.
Mexico City's Mayor Claudia Sheinbaum posted a video on Twitter thanking "the champions and those who made this great triumph possible."
Erik "El Terrible" Morales, Andy Ruiz Jr., Oscar Valdez, Jackie Nava, Humberto "Chiquita" Gonzalez, Miguel Berchelt, Jose "Pipino" Cuevas, Alfonso Zamora, Jose Luis Bueno, Jose Antonio "Jaguar" Aguirre, Ganigan Lopez, Adrian "Confesor" Hernandez, Ana Maria Torres and Alan David Picasso were the other instructors in the mega boxing class, according to ESPN.
Hundreds of people had gathered early for the enormous class in Zocalo plaza, which began with a tai-chi warmup, followed by a review of basic boxing movements and then practice in various combinations of blows.
Carmen Perez, 16, an urban dance devotee, said she was thrilled to take part.
"There is a very beautiful energy - very joyful, a lot of joy," she told news agency AFP.
The event was organized by the Mexico City government, which had recruited such prominent figures as American actor Sylvester Stallone - Rocky Balboa on the big screen - and boxer Saul "Canelo" Alvarez to promote it.
Mexico City, with nine million residents, holds several Guinness records.
They include the biggest serving of packaged tacos (2,712 pounds or 1,230 kilograms), the largest number of free Wi-Fi hotspots in an urban area (21,500), and the largest number of people playing foosball simultaneously (1,080).