A flock of storks deliver babies while circus animals are being transported by train from their “Winter Quarters”. Mrs. Jumbo, one of the elephants, receives her baby who is soon tormented by the other (female) elephants because of his large ears, and they nickname him “Dumbo”.
Once the circus is assembled, Mrs. Jumbo loses her temper at a group of boys for tormenting Dumbo, and is locked up and deemed mad. Dumbo is shunned by the other elephants and with no mother to care for him, he is now alone. Timothy Q. Mouse, who feels sympathy for Dumbo and becomes determined to make him happy again, appoints himself as Dumbo’s mentor and protector.
The circus director makes Dumbo the top of an elephant pyramid stunt, but Dumbo trips over his ears and misses his target, injuring the other elephants and bringing down the big top. Dumbo is made a clown as a result, and plays the main role in an act that involves him falling into a vat of pie filling. Despite his newfound popularity and fame, Dumbo dislikes this job and is now more miserable than ever.
To cheer Dumbo up, Timothy takes him to visit his mother. On the way back, Dumbo cries and then starts to hiccup, so Timothy takes him for a drink of water from a bucket which, unknown to them, has accidentally had a bottle of champagne knocked into it. As a result, Dumbo and Timothy both become drunk and see hallucinations of pink elephants.
The next morning, Dumbo and Timothy wake up in a tree. Timothy wonders how they got up in the tree, and concludes that Dumbo flew up there using his large ears as wings. With the help from a group of crows, Timothy is able to get Dumbo to fly again, using a psychological trick of a “magic feather” to boost his confidence.
Back at the circus, Dumbo performs a stunt which involves jumping from a high building, this time, from a much higher platform. On the way down, Dumbo loses the feather; Timothy quickly tells him that the feather was never magical, and that he is still able to fly. Dumbo is able to pull out of the dive and flies around the circus, finally striking back at his tormentors as a stunned audience looks on in amazement.
After this performance, Dumbo becomes a media sensation, Timothy becomes his manager, and Dumbo and Mrs. Jumbo are given a private car on the circus train.