Nawaki. They look alike, think alike, and act alike. Though, Nawaki may be more disciplined than Naruto. So I guess it's going to be Konohamaru. Remember, Nawaki, Konohamaru, and Naruto are descended from Kage (Nawaki is the 1st's grandson, Konohamaru is the 3rd's grandson, and Naruto is the 4th's son). They're both perverts, too.
Kushina ( Naruto's mother ).
The similarity in the face.
Minato ( Naruto's father ).
The similarity in the eyes and hair.
Naruto's Kage Bunshins.
Kiba always reminded me a lot of Naruto in his mannerisms.
Personality wise I always compared rock lee to Naruto because they both never give up.