An as an act of protest, occupation is the entry into and holding of a building, space or symbolic site. As such, occupations often combine some of the following elements: a challenge to ownership of the space involved, an effort to gain public attention, the practical use of the facilities occupied, and a redefinition of the occupied space. Occupations may be conducted with varying degrees of physical force to obtain and defend the place occupied. Occupations may be brief or they may extend for weeks, months or years. In some cases of long-term occupation, the term protest camp may be applied, although occupation often connotes the use of space without permission or in defiance of governmental authority.
Occupation, as a means of achieving change, emerged out of worker struggles that sought everything from higher wages to the abolition of capitalism. Often called a sit-down strike, it is a form of civil disobedience in which an organized group of workers, usually employed at a factory or other centralized location, take possession of the workplace by "sitting down" at their stations, effectively preventing their employers from replacing them with strikebreakers or, in some cases, moving production to other locations.
The recovered factories in Argentina is an example of workplace occupations moving beyond addressing workplace grievances, to demanding a change in ownership of the means of production.
The Industrial Workers of the World were the first American union to use it, while the United Auto Workers staged successful sit-down strikes in the 1930s, most famously in the Flint Sit-Down Strike of 1936-1937. Sit-down strikes were declared illegal by the US supreme court, but are still used by unions such as the UMWA in the Pittston strike, and the workers at the Republic Windows and Doors factory in Chicago.
Notable protest occupations 
- The several massive occupations of improductive land in Brazil by the largest mass movement of the world, the Movimento dos Trabalhadores Rurais Sem Terra, from 1973 up to now .
- The occupation of the Wisconsin State Capitol in Madison, Wisconsin in February, 2011 as part of the 2011 Wisconsin protests over labor rights, a precursor to the Occupy Wall Street movement.
- Occupy Wall Street, which helped spawn worldwide Occupy movement that is still ongoing
- 2011–2012 Spanish protests
- Tahrir Square during the 2011 Egyptian revolution
- The occupation of some university buildings in the UK in November 2010 and early 2011 in response to cuts by the coalition Conservative-Liberal Democrat government including those to public services, welfare handouts and all levels of education (notably the increase of tuition fees in combination to funding cuts).
- The tent city known as "Democracy Village" erected in Parliament Square in London, in 2010.
- The wave of Student Occupations at universities in the UK in early 2009  .
- The occupations of university buildings during the 2009 California college tuition hike protests.
- The flux of student occupations at universities in New York City over the 2008-9 year, including NYU and The New School.
- The February 2008 occupation of Symphony Way by the Symphony Way Pavement Dwellers after the largest home invasion in South Africa's history. Residents have occupied the main thoroughfare for 1 year and 9 months.
- The occupation of Oaxaca City for 150 days during the 2006 Oaxaca protests.
- Cedar Revolution
- The Tiananmen Square protests of 1989.
- The Greenham Common Women's Peace Camp in England which began protesting the placement of nuclear-armed cruise missiles in 1981.
- The American Indian Movement occupation at Wounded Knee, South Dakota (1973)
- The 1969 occupation of Alcatraz by American Indians.
- The 1969 occupation of City College by a group consisting largely of Black and Puerto Rican students that demanded and won open admissions at CUNY.
- The 1968 Columbia Student Strike.
- The 1936-37 GM Sit-Down Strike, in Flint, Michigan.
Major forms of occupation as protest include