The WBC and IBF welterweight champion was taken to intensive care after the crash in Dallas.
Boxer Errol Spence Jr is expected to make a full recovery after a car crash.
The WBC and IBF welterweight champion was taken to intensive care after the crash in Dallas, Texas.
A statement from his representatives at Premier Boxing said Spence "is resting with his family by his side.
"The Spences want to thank everyone for their prayers and well wishes and are extremely grateful to the Dallas first responders who rushed to the scene and the doctors who are taking care of him."
A statement from Dallas Police Department said Spence, driving a Ferrari and not wearing a seatbelt, was ejected from the vehicle when it "flipped multiple times" in the early hours of Thursday morning.
The 29-year-old was subsequently taken to an intensive care unit at a local hospital.
The statement read: "On October 10, 2019, at 2:53am, a white Ferrari was travelling at a high rate of speed northbound in the 500 block S. Riverfront Boulevard.
"The Ferrari veered left over the centre median onto the southbound lanes and flipped multiple times ejecting the driver who was not wearing a seatbelt.
"The driver, Errol Spence Jr, 29-years-old, was taken to an area hospital where he remains in ICU. He is expected to live. The cause of the accident is undetermined at this time."
Spence added the WBC belt to his IBF title last month when he beat fellow American Shawn Porter in Los Angeles, and is unbeaten in 26 fights as a professional.
He has held the IBF crown since taking it from Kell Brook with victory over the Briton at Sheffield United's Bramall Lane in 2017.
Brook took to Twitter to offer his wishes to Spence, saying: "Get well soon champ! Thought (sic) are with you and wishing you a full and speedy recovery."
Multiple world champion Terence Crawford also tweeted: "Praying for you champ @ErrolSpenceJr get well we fighters I know you will."