Anthony "Showtime" Pettis wants next ... telling TMZ Sports he's coming for BOTH of Conor McGregor's UFC belts.
Pettis -- the #6 ranked featherweight in the world -- was definitely impressed with the Notorious one after he beat down Eddie Alvarez at UFC 205 ... but says it's his turn to fight the champ.
"If he stays fighting, I'm coming for the 145 pound strap AND that 155 pound strap."
We know these two don't like each other -- but there's a LONG list of UFC stars hoping for a chance to punch him in the face.
Stay tuned ...