Jacksonville Jaguars running back Maurice Jones-Drew has been charged with battery after allegedly KO'ing a security guard at the Conch House in St. Augustine, FL ... TMZ has learned.

According to the police report obtained by TMZ, MJD is accused of striking the security guard with a closed fist on the guard's left cheek, knocking him out.

According to cops, the punch was intentional.

The incident went down during "Reggae Sundays" at the Conch House restaurant on May 26.

According to the police report, witnesses say ... MJD's buddy was told by security to stop touching a young female. The buddy allegedly "slapped" a security guard on his chest ... and a melee ensued.

One of the security guards reportedly put MJD's friend in a headlock to stop the fight ... and that's when MJD stepped in and clocked the guard.