Gustav Adolf Fischer (3 March 1848 – 11 November 1886, Berlin) was a German explorer of East Africa.

Gustav Adolf Fischer was born in Barmen (now part of the city of Wuppertal) in Germany on 3 March 1848.

On leaving school in 1869 he studied medicine and natural sciences in Bonn, Berlin and then Würzburg where he obtained a doctorate.

With the support of the Geographic Society in Hamburg he visited the Maasai country in 1882 and penetrated from the mouth of the Pangani River to Lake Naivasha.

Equipped with funds by the brother of Wilhelm Junker, an explorer, who with Emin Pasha and Gaetano Casati had been lost in the equatorial provinces, he organized a relief expedition which, however, was compelled to return after reaching Lake Victoria.