The 172nd Infantry Brigade was a light infantry brigade of the United States Army stationed at Fort Wainwright, Alaska and later moved its headquarters to Grafenwöhr, Germany. An active duty independent brigade, it was part of V Corps and was one of five active-duty, separate, brigade combat teams in the U.S. Army before its most recent inactivation on 31 May 2013.

First activated in 1917, the brigade was deployed to France during World War I and used to reinforce front-line units. The brigade's actions in France during that time are not completely clear. It would later be converted to a reconnaissance unit that was deployed during World War II and saw several months of combat in the European Theatre. The brigade has multiple tours of duty in Operation Iraqi Freedom from 2005 until 2006 and from 2008 until 2010 and in Operation Enduring Freedom from 2011 until 2012. Its infamous 16-month deployment was one of the longest deployments for a unit serving in the OIF campaign. Most recently the brigade served a 12-month tour in Afghanistan from 2011 until 2012.

The unit has been activated and inactivated numerous times, and has also seen several redesignations. The 172nd was one of the first brigade combat teams before it was deactivated in 2006. Reactivated in 2008 from another reflagged unit, it immediately prepared for another tour of duty in Iraq. Following a series of budget cuts and force structure reductions, the unit formally inactivated on 31 May 2013 in Grafenwöhr, Germany.