Mad Dog, in comics, may refer to:
Mad Dog (DC Comics), a DC Comics supervillain
Mad Dog, a number of Marvel Comics characters:
Mad Dog (Marvel Comics), a Marvel/Timely Comics supervillain
Mad Dog Rassitano, a Marvel Comics character and fictional SWAT member
Mad Dog #336 was an alias used by Peter Parker
Mad Dog #736 was an alias used by Captain Zero
Mad Dog #2020 was an alias used by Brainstorm
"Mad Dog" Martin was a character who appeared in Combat Kelly and his Deadly Dozen
"Mad Dog", a Marvel comics title based on the fictional comic of the same name in the sitcom Bob.