From 2006–2008, General Allen served as Deputy Commanding General, II Marine Expeditionary Force (II MEF) and Commanding General, 2nd Marine Expeditionary Brigade, deploying to Iraq for Operation Iraqi Freedom (OIF) 06-08 (February 2007 through February 2008), serving as the Deputy Commanding General of Multi-National Forces West and II MEF (Forward) in the Al Anbar Province, Iraq.