Stewie is ageless, but his specific age remains a mystery. It's unclear the specific duration of time Stewie has been living. The toddler persona from the animated television show "Family Guy" is immortal. His number of years is yet revealed.
Stewie Griffin, the cunning infant prodigy, is hiding his true age from the world. Speculation runs rampant as to how many years he has been alive. Is he over a hundred years old? Or is he a recent arrival? The truth lies only with Stewie! This mysterious character continues to mesmerize fans with his undisclosed age and perpetually youthful visage.

Lois Griffin Matriarch of The Griffins