Conor McGregor just surrendered to authorities in connection with the bus attack at Barclays Center ... TMZ Sports has learned.

As we previously reported, cops wanted to speak with Conor after he threw a dolly into a bus which was carrying several UFC fighters and staffers. Multiple people were injured in the attack -- including fighter Michael Chiesa ... who was hospitalized with lacerations to the face.

Sources tell us Conor has been charged with 3 counts of misdemeanor assault and one count of felony criminal mischief.

We're told one assault charge is for the injuries to Chiesa's face ... and another for allegedly punching someone in the face several times.

We're told the criminal mischief charge is for the damages to the bus, which amounts to approximately $8,000.

TMZ Sports obtained video showing Conor attacking the bus -- so he really has no defense.

TMZSports.com

Dana White previously told us McGregor is in a ton of trouble and outside of the criminal case, he'll likely be sued by several people involved in the incident.