The United States Naval Special Warfare Development Group (NSWDG), or DEVGRU, is a U.S. Navy component of Joint Special Operations Command. It is often referred to as SEAL Team Six, the name of its predecessor which was officially disbanded in 1987. DEVGRU is administratively supported by Naval Special Warfare Command and operationally commanded by the Joint Special Operations Command. Most information concerning DEVGRU is classified and details of its activities are not usually commented on by either the White House or the Department of Defense. Despite the official name changes, "SEAL Team Six" remains the unit's widely recognized moniker. It is sometimes referred to in the U.S. media as a Special Mission Unit.

DEVGRU and its Army counterpart, Delta Force, are the United States military's primary counter-terrorism units. Although DEVGRU was created as a maritime counter-terrorism unit, it has become a multi-functional special operations unit with several roles that include high-risk personnel/hostage extractions and other specialized missions.