William Duer is the name of:

• William Duer (Continental Congressman) (1743–1799), New York speculator, Continental Congressman and Assistant Secretary of the Treasury
• William Alexander Duer (1780–1858), U.S. jurist, President of Columbia University, son of the Continental Congressman
• William Duer (U.S. Congressman) (1805–1879), U.S. lawyer and Congressman from New York City; grandson of the Continental Congressman

• 1859 (year)
• 185 CE
• 185 chairs
• 185 Empty Chairs
• 185 empty chairs
• 185 empty white chairs
• 185P/Petriew
• 185th Airborne Division Folgore
• 185th Air Refueling Squadron
• 185th Air Transport Squadron
• 185th Artillery Paratroopers Regiment "Folgore"
• 185th Aviation Regiment
• 185th Aviation Regiment (United States)
• 185th Division (People's Republic of China)
• 185th Infantry Division (German Empire)
• 185th New York Volunteer Infantry
• 185th Tactical Airlift Squadron
• 185 white chairs
• 185 (year)
• 18/6
• 186007 Guilleminet
• (186024) 2001 QG207
• 1860-61 New Zealand general election
• 18609 Shinobuyama
• 1860 AD