Kapitänleutnant Wilhelm Otto Walther Schwieger (7 April 1885 – 5 September 1917) was a German military officer.

As a submarine captain, Schwieger has been noted for his cavalier approach to attacking without being sure about the identity or nationality of his target, sometimes in breach of orders to the contrary.

On 7 May 1915, Schwieger was responsible for the U-20 sinking passenger liner RMS Lusitania leading to the deaths of 1,199 people, an event that played a role in the United States' later entry into World War I.

On 31 May 1917, his U-boat U-88 sank the Miyazaki Maru during that ship's voyage from Yokohama to London, causing the loss of eight lives.

Schwieger was represented in the docudrama "Lusitania: Terror At Sea" in 2007, where he was played by actor Florian Panzner.