From Wiki:
Full name Penny’s last name has not been revealed, though co-creator Bill Prady stated that it eventually will be.
According to this wiki it is Queen. But, anyone can edit those things, so who knows…
@cazzie not sure why they’d keep us in suspence though, it’s not exactly quintessential to the plot.
@FPSMadPaul but, maybe it is… hrmmmm…
I am a fan of Big Bang and to be honest I don’t think penny have a last name… Money Penny would be cool…
Penny Nickel Dime is her full name.
The reason I ask is we have just adopted a cat called Leonard and I’m thinking if we get another cat (if it’s a girl) we should call her Penny. Then that got me thinking about Penny’s full name as we know the rest of their gull names.