Üstündağ is a Turkish surname meaning "superior mountain". Notable people with the surname include:
Efe Üstündağ (born 1977), Turkish tennis player Cem Üstündag (born 2001), Austrian footballer Mustafa Üstündağ (actor) (born 1977), Turkish actor Mustafa Üstündağ (politician) (1933–1983), Turkish politician Nida Eliz Üstündağ (born 1996), Turkish swimmer Orhan Üstündağ (born 1967), Turkish footballer Taner Üstündağ (born 1971), Turkish alpine skier