Offset is being sued over an alleged altercation at a dispensary … with a security guard claiming the rapper attacked him.

Jim Sanchez is suing the rapper … saying he’s a security guard who was working at MedMen LAX back in March when Offset and his friends allegedly came to the store.

In the lawsuit, Sanchez claims he asked Offset to show identification which he says set off the rapper. Sanchez claims Offset “became hostile, verbally confrontational, and physically attacked Plaintiff by striking him in the face.”

Sanchez is suing Offset for assault, battery and intentional affliction of emotional distress.

We told you about this alleged incident back in March … which Offset’s rep called complete and total BS.

At the time, Offset’s side claimed the security guard rushed at the rapper and even spat on him, which caused a fight to break out.

Multiple sources told TMZ Hip Hop the rapper punched the guard … who they allege then used a can of mace on Offset and his crew.