It happened at approximately 10 p.m. near 13th and Walnut streets.
Witnesses reportedly told police the stabbing took place after a fight broke out outside a bar.
One of the victims was stabbed multiple times in the back, police say.
That victim was transported to Jefferson University Hospital in an unknown condition.
Authorities did not release any details on the other two stabbing victims.
There is also no word on what may have sparked the initial fight.
No arrests have been made in this case. Anyone with information on this incident is asked to contact Philadelphia police.