The 48-year-old singer and 37-year-old actor attended the awards show at The Forum in Inglewood, Calif., with their 6-year-old twins, daughter Monroe and son Moroccan.
Carey and Cannon wore matching outfits with Monroe and Moroccan, respectively. Carey and Monroe sported black pants with leather jackets, while Cannon and Moroccan wore white sweatsuits with orange detail.
Carey and Cannon split in 2014 after six years of marriage, but have remained friendly since.
"He's a good guy," the singer said of Cannon in an interview with Entertainment Tonight in June.
"It's not that hard to make it work," she added of co-parenting. "Now we can laugh and joke and do the good parts of when we had a relationship."
Carey is presently dating Bryan Tanaka, with whom she attended a Golden Globes after-party in January. Cannon welcomed a son, Golden Sagon, with ex-girlfriend Brittany Bell in February 2017.