A 2-year-old Indiana boy accidentally shot his mother with a semi-automatic pistol, seriously wounding her, authorities said.

The 40-year-old woman, who was not immediately identified, was shot in the torso early Wednesday when her son found the weapon in the family’s home in an unincorporated area of Hendricks County on US Highway 36, sheriff officials told The Post.

The boy’s 5-year-old brother, who was also home at the time, managed to call for help following the shooting, which appeared to be accidental, Capt. Amanda Goings said.

It was not immediately clear whether the boy called 911 or reached out for help to a relative who then contacted authorities, Goings said.

The wounded mother was rushed to a hospital in Indianapolis in serious condition. She was later upgraded to stable, sheriff’s officials said.

Both children who were at the home were not hurt, Goings said.

Child welfare officials and detectives from the Hendricks County Sheriff’s Office are looking into the incident.