"One weekend a month, two weeks a year" is a former recruiting slogan used by the U.S. Army National Guard. It indicated the amount of time an individual would need to spend actively in the Guard to be a Guardsman with benefits. Though never officially, it was also informally used by Air National Guard, U.S. Army Reserve, U.S. Naval Reserve, U.S. Marine Corps Reserve, U.S. Air Force Reserve and U.S. Coast Guard Reserve personnel in describing their similar military time commitment.
It was dropped during the Iraq War after it became clear that National Guardsmen and Reservists were now serving considerably more time in service, especially on active military duty on extended overseas deployments in the Southwest Asia combat zone.
The slogan "one weekend a month, two weeks a year" has been most commonly seen by Americans in recruiting ads for the National Guard, especially in the 1970s, 1980s and 1990s. Although the slogan is only sometimes used directly in advertising, as of 2004 [update] it was used to describe the duties of at least some military posts. 
The slogan has also been used to contrast the commitment that a National Guard member would give during those times when his country was not at war.
Other Reserve and National Guard forces have used this slogan as something against which they can contrast their own dedication,  showing that, as members of combat aviation units or special forces, they are not mere "weekend warriors".
Understanding the meaning of the slogan to those enlisted in the National Guard requires understanding the historical context in which it was given. During World War II, the National Guard was called up to defend their country, and this was repeated in the Korean War even when American soil was not directly threatened. At this time, joining a reserve component could clearly be seen as a route to service overseas. However, at the time of the Vietnam War, President Johnson made it clear that the National Guard's role was to defend the country and not to be involved in overseas adventures. At the time, this meant that those who joined the force could be fairly sure of not seeing action in the war, and became a pejorative term.
These forces are expected to act as a second line of defense, primarily motivated by the fact that they are defending their own homes and families.
The commitment to Iraq and more recently, subsequent engagements, conflicts, and operations (primarily, and more specifically; those related to the Global War on Terrorism) has meant that many members of the National Guard feel the terms in which they understood their recruitment have been breached. The slogan has now become known in a changed form, "One weekend a month, my ass,"  as a comment on the perceived mistreatment of the National Guard and the Reserve.
During some periods of the 2003 war in Iraq, the National Guard ( Army National Guard and Air National Guard) represented 41% of all U.S. military personnel deployed.  The majority are supposed to serve for six months or a year. However, some specialists in the reserve forces have been required to serve for up to two years.
In the meantime, the role of the National Guard which, in the Vietnam War, largely revolved around home defense and policing,  has changed so that in Iraq "about 20 percent of the U.S. military deaths in that conflict"  have been carried by Reserve and Guard units.
It has been claimed in the U.S. media that the change in expectations on the National Guard is a deliberate change in policy by military planners in response to the Vietnam War.  The need to use the National Guard is designed to reduce the possibility of "half-hearted" wars in future. Actual legal changes were made by the US Congress and in the 1980s which moved final decision for their use as military forces from their commanders in chief, the state governors, to the federal government. These new laws were successfully defended against challenges from state governors in the U.S. Supreme Court. 
In July 2012, the Chief of Staff of the Army, General Ray Odierno, indicated that he intended to change the Army National Guard's annual peacetime active duty commitment from two weeks per year to up to seven weeks per year, in addition to the weekend a month, which would not change. The changes come as the Army plans to reduce the number of full-time soldiers, and going forward relies increasingly on the Army National Guard. "How do we sustain the readiness and experience that we've gained in the National Guard and Reserve component?" Odierno asked. "That's what we've been working on." 
"One weekend a month, two weeks a year" was also formerly used as a descriptor in television advertisements for the Australian Army Reserve.
- "10 Steps to Joining the Military: Step 4: Meet the recruiter". Military.com. Retrieved 2006-05-12. "As a member of the AGR [Active Guard and Reserve] you are assigned a full time mobilization slot or billet in the unit you serve in on that one weekend a month/two weeks a year."
- "The Special Forces Soldier". Alabama National Guard. Retrieved 2006-05-12. "… the Guard SF soldier operates way outside the normal 'one weekend a month - two weeks a year' of regular National Guard duty. The monthly drills and yearly deployments are nearly twice as long as the normal Guard requirements."
- Stewart, Richard Winship (2005). "The Global War on Terrorism". American Military History: The United States Army in a Global Era, 1917–2003 (PDF). p. 495. Retrieved 2013-07-21.
- "One Weekend a Month—My Ass!!". Archived from the original (jpeg) on March 30, 2007. Retrieved 2013-07-21.
- U.S. Army Reserve. "Photo Gallery". Center for Army Lessons Learned (CALL). Archived from the original on 2006-02-24. Retrieved 2006-05-12.
- Graham, Bradley (July 1, 2005). "Army to Use Fewer National Guard Troops in Iraq". Washington Post. Retrieved 2006-05-17.
- Rigney Jr., Ernest G. "The Kent State Tragedy". The Vietnam War, 25 Years After. College of Charleston. Archived from the original on 2006-02-21. Retrieved 2006-05-12.
- Dodge, Dani (June 27, 2004). "New war role strains reserves". Ventura County Star. Retrieved 2006-05-12.
- "Calling on the National Guard". The Week. March 19, 2004. Archived from the original on March 7, 2016. Retrieved 2006-05-13.
- "National Guard - Tug of War". Governing Magazine. August 2004. Retrieved 2012-07-27.
- "Army to expand citizen soldiers' training periods". USA Today. July 30, 2012. Retrieved 2013-01-22.