In 1912 New Orleans, a seamstress, Eudora, is reading the story of The Frog Prince to her daughter, Tiana, and her friend, Charlotte La Bouff. Charlotte finds the story to be romantic, while Tiana proclaims she will never kiss a frog. Fourteen years later, Tiana has grown into an aspiring young chef who works as a waitress for two local diners, so she can save enough money to start her own restaurant, a dream she shared with her deceased father James.
Prince Naveen of Maldonia arrives in New Orleans to better his financial situation. After being cut off by his parents, Naveen intends to marry a rich southern belle, and Charlotte is the perfect candidate. Eli “Big Daddy” La Bouff, a rich sugar baron and Charlotte’s father, is hosting a masquerade ball in Naveen’s honor. Charlotte hires Tiana to make beignets for the ball, giving her enough money to buy an old sugar mill to convert into her restaurant.
Meanwhile, Naveen and his valet, Lawrence, encounter voodoo witch doctor Dr. Facilier. Inviting them into his emporium, Facilier convinces them that he can make their dreams come true, but neither man gets what they are expecting; Naveen becomes a frog, while Lawrence is given a voodoo charm that makes him resemble Naveen. Facilier intends for Lawrence to marry Charlotte, after which he will kill Big Daddy and claim his fortune.
At the ball, Tiana discovers she may lose the mill to a higher bidder. Tiana then meets Naveen, who, believing her to be a princess because of her costume, asks her to kiss him and break Facilier’s spell. In exchange for the money needed, Tiana accepts, but when she kisses Naveen, she is turned into a frog herself. A chase ensues, and Tiana and Naveen escape to a bayou.