Chris Griffen (9.7inches) It’s stated that chris has a monster penis and peter is ashamed of it.
Stewie Griffin (2.1 inches) He’s a baby so it’s small but it’s larger than peters
Peter Griffin (1.7 inches) It’s constantly stated that peter has a small pecker and it even did a penis measuring contest with Stewie which he lost.
Brian Griffin: The average penis size of a labrador Retriever seems to be from 6.5-8 inches long which brian is based on. however his ex girlfriend seemed to think he had a tiny penis when confronted in an intervention of all his ex’s orchestrated by stewie. so probably around 3-4 inches
Lois Griffin: (0.0 inches) (Obvious since she’s female
Meg Griffin (0.0 inches)