ISIS militants hung his body from a column in Palmyra's main square after beheading him on Tuesday.
The octogenarian archaeologist had spent more than 50 years working on the Unesco World Heritage site Palmyra.
Khaled was head of antiquities at the ancient ruins, which is considered one of the most important historic sites in the Middle East.
The group has previously destroyed ancient ruins in Syria and Iraq but it is unclear how much damage they have caused at Palmyra.
Read More: Things to know about Syrian city of Palymyra
Syrian troops have sought to drive ISIS militants out of the area in recent months and there has been fierce fighting in nearby towns - but the group remains in control of Palmyra.
ISIS militants destroyed artifacts in Syrian city of Palmyra in June and July.