Battle of Wanat begins when Taliban and al-Qaeda guerrillas attack US Army and Afghan National Army troops in Afghanistan. The U.S. deaths were, at that time, the most in a single battle since the beginning of operations in 2001.

The Battle of Wanat took place on July 13, 2008, when around 200 Taliban insurgents attacked American troops stationed near Quam, in the Waygal district of Afghanistan's far eastern Nuristan province. The distant position was primarily defended by United States Army soldiers with 2nd Platoon, Chosen Company, 2nd Battalion, 503rd Infantry Regiment (Airborne), 173rd Airborne Brigade Combat Team.

The Taliban encircled the remote base and its observation post, attacking it from Quam and surrounding farmland. They destroyed much of the U.S. troops' heavy munitions, broke through their lines, and entered the main base before being finally repelled by artillery and aircraft. The United States claimed to have killed at least 21 Taliban fighters for nine of its own soldiers killed and 27 wounded, together with four Afghan National Army (ANA) soldiers wounded.One of several attacks on remote outposts, the Battle of Wanat has been described as among the bloodiest Taliban attacks of the war. In contrast to previous assaults, from roadside bombings to haphazard ambushes, this attack was well-coordinated; fighters across different insurgent groups were able to precisely target key equipment, such as a wire-guided missile launcher, through a sustained and disciplined effort.

The battle became the focus of debate in the United States, generating "... a great deal of interest and scrutiny among military professionals and from outside observers ..." mainly due to the relatively "... significant number of coalition casualties ..." Several investigations were launched into events leading up to the battle. The initial investigation was completed in August 2008. In July 2009, Senator James Webb requested that the U.S. Army formally investigate the battle and previous investigation. Lieutenant General Richard F. Natonski conducted another investigation in late 2009 which led to orders of reprimand for the chain of command. In June 2010, the U.S. Army revoked the reprimands. They stated that no negligence was involved and said of the soldiers that "... by their valor and their skill, they successfully defended their positions and defeated a determined, skillful, and adaptable enemy."