Walter Franz Koch (18 May 1870 – 26 December 1947) was a Saxon and German diplomat, lawyer and politician for the liberal German People's Party, who served as Saxon Minister of State for the Interior, Saxon Ambassador to Prague and Berlin, and finally as German Ambassador to Prague.
From 1909 to 1918 he was a legal adviser in the Ministry of the Interior of the Kingdom of Saxony.
From 18 October 1918 to 14 November 1918 he served as the Minister of the Interior of Saxony, which was transformed from a kingdom into a republic during his tenure.
From 1919 to 1921 he was the Special Representative (Ambassador) of Saxony in Prague, and then the Saxon Ambassador to Berlin, representing the Saxon Government vis-à-vis the Prussian and federal government.
In September 1927 in the Church of Saint Nicholas, their daughter Elisabeth Helene was married to the Austrian Consul-General in Prague Herbert, Count of Schallenberg.