Johann Karl Friedrich August Borsig (German pronunciation: [ˈjoːhan ˈkaʁl ˈfʁiːdʁɪç ˈʔaʊɡʊst ˈbɔʁzɪç]; 23 June 1804 – 6 July 1854) was a German businessman who founded the Borsig-Werke factory.
Borsig was born in Breslau (Wrocław), the son of cuirassier and carpenter foreman Johann George Borsig. After learning his father's trade, he first attended the Königliche Provinzial-Kunst- und Bauschule (Royal Provincial Art and Building school), then until fall of 1825 the Königliche Gewerbe-Institut (Royal Institute of Trade). He received his practical training in engine construction at the Neue Berliner Eisengießerei (New Iron Foundry of Berlin) of F. A. Egells, where one of his first tasks was the assembly of a steam engine in Waldenburg, Silesia. After the successful completion of this task, Borsig was made factory manager for eight years. In 1828, he married Louise Pahl; they had one son, Albert.