Internet shorthand for "Got to go". Also, it can mean "good to go", depending on the context.
Good to go:
"Say, I'm heading out. You coming?"

Got to go:
"Shoot, it's almost midnight. gtg."
by Mephianse September 9, 2004
when you don't have the time to write a long bye.
by kel December 10, 2003
Means gotta go. But it has evolved into something more like i dont wanna txt you anymore
Person: Whats up?
Person 2: Nothinnnn.
Person:hey gtg bye
by personthatsubmits stuff September 1, 2010
Good to go.

Commonly confused with 'g2g' which means "got to go". They are different, and 'gtg' is normally used in online games to indicate a participant's "ready status." It is seeing common usage today as indicating in the example.
"Are you ready to hit the clubs? I'm gtg!"
by kohner March 20, 2009
Good to Go. Can mean leaving or having to go. In military slang it is similar to acknowledged.
"Sergeant, we are rolling out at zero-shit-thirty" "Good to go Sir (gtg). I will pass word"
by wertyy102 October 25, 2016