Hans Otto Theodor von Bülow (28 December 1827 – 22 November 1901) was a German diplomat.

[3] Bülow studied law at Friedrich-Wilhelms-Universität in Berlin, Ruprecht-Karls-Universität in Heidelberg, and University of Halle in Saale.

Due to disagreements between Kaiser Wilhelm II and the Reich Chancellor and Prussian Prime Minister Bismarck, which led to Bismarck's resignation at Wilhelm II's insistence on 18 March 1890 and personnel changes in the diplomatic service.

The generally difficult relationship between the Holy See and the religiously reformed Prussia also led to disagreements in the German diplomatic Corps, which is why the Prussian envoy to the Vatican, Kurd von Schlözer was replaced in 1892 with von Bülow as distinguished envoy to the Holy See in the Vatican, holding the office of Prussian ambassador until his retirement in 1898.

Before her death on 24 December 1861 in Berlin, they were the parents of one son:[2] After the death of his first wife, he married Martha Florowna von Doliva-Dobrovolsky (1830–1891), widow of Eugen von Schele and daughter of Florian Dolivo-Dobrovolsky, on 4 October 1865, in St. Petersburg, Russia.