The following are events related to the Global War On Terrorism (GWOT) that took place on this day.

Casualties on December 20:

• CLEARY, MICHAEL JOSEPH – December 20, 2005
• NAPUTI, RICHARD JUNIOR DE GRACIA – December 20, 2005
• DYKMAN, SCOTT DOUGLAS – December 20, 2006
• MCMILLAN, JACOB GERALD – December 20, 2006
• SEBASTIEN, MYLES CODY – December 20, 2006
• VOLKER, ROBERT JAMES – December 20, 2006
• RAY, JEREMY E – December 20, 2007
• DEAN, JONATHAN WAYNE – December 20, 2008
• HINKEFENT, COLEMAN WAYNE – December 20, 2008
• JOHNSON, ROBERT LYMAN – December 20, 2008
• KROPOV, SERGE – December 20, 2009
• CHAVES, AVADON ALFRED – December 20, 2017