Toivo Nestori Aro (ne Ahlstedt, February 9, 1887 – October 8, 1962) was a Finnish diver who competed in the 1908 Summer Olympics and in the 1912 Summer Olympics.
He was born and died in Helsinki.
In 1908 he was eliminated in the semi-finals of the 10 metre platform event.
Four years later he finished fifth in the plain high diving competition and eighth in the 10 metre platform event of the 1912 Games.