Middle school (also known as intermediate school or junior high school) covers a period of education that straddles primary/elementary education and secondary education, serving as a bridge between the two. The terms can be used in different ways in different countries, sometimes interchangeably.
Thus in some governmental and institutional contexts, "Middle school" may be used as no more than an alternative name to "junior high school", or it might imply a pedagogical shift away from primary and secondary school practices. The concept itself dates back to 1909, with the founding of Indianola Junior High School in Columbus, Ohio.

Middle School as a Pedagogy

Asia
In the People's Republic of China, middle schools (chuzhong or 初中) refer to years 7–9. It covers the last 3 years of the 9-year compulsory education, which is supposed to be free but in fact is subject to fees. At the end of the last year, the college-bound students take exams to enter high school (gaozhong or 高中) others wishing to continue their training may enter technical high school (中学专科/中专) or vocational school (职业学校).

China
In Japan, junior high schools, which cover years seven through nine, are called chū gakkō (中学校, literally, middle school). They are referred to as "junior high schools" in most conversations in English but are referred to by MEXT as "lower secondary schools". (See Secondary education in Japan.)

Japan
In the Republic of Korea, a middle school is called junghakgyo (중학교, 中學校) which includes grades 7 through 9.

South Korea
In India, middle school consists of classes 5th, 6th and 7th.

India
In Indonesia, a middle school is called Sekolah Menengah Pertama (SMP). It consists grades 7, 8, 9. Previously 1, 2, 3. For example SMPN 252 consists grade 7, 8, 9. And previously SLTP (Sekolah Lanjutan Tingkat Pertama) 252 consists grade 1, 2, 3

Indonesia
In the Philippines, what is referred to as middle school generally consists of the grades 4 through 6. In the Philippines, there is no such thing as Middle School. It goes Kindergarten, Grade One, Grade Two, Grade Three, Grade four, Grade Five, Grade Six, Grade 7(Some private schools), First Year High School, Second Year High School, Third Year High School, and finally Fourth Year of High School.

The Philippines
Taiwanese junior high schools (3-year) were originally called chuzhong (初級中學, 初中; "primary middle school"). However, in August 1968, they were renamed guozhong (國民中學, 國中; "citizen middle school") when they became free of charge and compulsory. Private middle school nowadays are still called chuzhong. Taiwanese junior high schools are attended normally by those older than twelve. Accompanied with the switch from junior high to middle school was the cancellation of entrance examination needed to enter senior high school.

Taiwan

Australasia
In 1996 and 1997 a national conference met to develop what became known as the National Middle Schooling Project, which aimed to develop a common Australian view of
As of 2007, the Northern Territory has introduced a three tier system featuring Middle Schools for years 7-9 (approx ages 11-14) and high school year 10-12.

early adolescent needs
guiding principles for educators
appropriate strategies to foster positive adolescent learning. Australia
In New Zealand intermediate schools cover years 7 and 8 (formerly known as form 1 and 2) in areas where the local primary schools teach year 1 to year 6 students. Many primary schools however, do teach year 7 and 8. These primary schools may have a relationship with a nearby intermediate school to teach manual training classes such as woodwork.
Recently, however, Junior High Schools covering years 7-10 (the four years between primary and NCEA, the national secondary qualification). The first was Albany Junior High School in Albany, Auckland.

New Zealand

Europe
In the countries of former Yugoslavia, srednja škola (literally translated as Middle School) refers to age between 14 and half - 15 and 18, and lasts 2-4 years since elementary school (which lasts 8 or 9 years). The final four years of elementary school are actually what would be called junior high school in USA. Students have up to 12-13 different subjects in each school year (most of them only two 45-minute class periods per week). For example, 8th grade students do not have one subject called Science but three separate subjects called Chemistry, Physics and Biology.

Bosnia, Croatia, Montenegro, Serbia, Slovenia
In the United Kingdom, some English Local Education Authorities introduced Middle Schools in the 1960s and 1970s. The notion of Middle Schools was mooted by the Plowden Report of 1967 which proposed a change to a three-tier model including First schools for children aged between 5 and 8, Middle Schools for 8–12 year-olds, and then Upper or High Schools for 12–16 year-olds. Some authorities introduced Middle Schools for ideological reasons, in line with the report, while others did so for more pragmatic reasons relating to the raising of the school leaving age in compulsory education to 16.
Different authorities introduced different age-range schools, although in the main, three models were used:
In addition, some schools were provided as combined schools catering for pupils in the 5–12 age range as a combined first and middle school.
Around 2000 middle and combined schools were in place in the early 1980s. However, that number began to fall in the later 1980s with the introduction of the National Curriculum. The new curriculum's splits in Key Stages at age 11 encouraged the majority of Local Education Authorities to return to a two-tier system of Primary and Secondary schools.
Under current legislation, all middle schools must be deemed either primary or secondary. Thus, schools which accept pupils up to age 12 are entitled middle-deemed-primary, while those accepting pupils aged 13 or over are entitled middle-deemed-secondary. For statistical purposes, such schools are often included under primary and secondary categories "as deemed". Notably, most schools also follow teaching patterns in line with their deemed status, with most deemed-primary schools offering a primary-style curriculum taught by one class teacher, and most deemed-secondary schools adopting a more specialist-centred approach.
Some Middle Schools still exist in various areas of England. The are supported by the National Middle Schools' Forum. A list of Middle Schools in England is available.
In Scotland a similar system was trialled in Grangemouth, Stirlingshire between 1975 and 1987. (See Grangemouth middle schools article)

5–8 First Schools, followed by 8–12 Middle Schools, as suggested by Plowden
5–9 First Schools, followed by 9–13 Middle Schools
5–10 First Schools followed by 10–13 Middle Schools, or Intermediate Schools United Kingdom
The definition of "middle school" is muddied somewhat because, in North American contexts, "secondary education" quite frequently means post-compulsory (High School level) education, encompassing such diverse institutions as "English as a second language" schooling, trade schools and certificate programs, as well as other intermediate options such as Junior colleges, four-year colleges and full universities.

Canada and the United States
In Mexico, the middle school system is called "secundaria" ("secondary") and comprises grades 7-9 and is completed after primary (1-6) and before preparatory (10-12).

Professional organizations

Arnold, J. "Needed: A Realistic Perspective of the Early Adolescent Learner." CLEARINGHOUSE 54:4 (1980).
Atwell, Nancie. "In the Middle: New Understanding About Writing, Reading, and Learning." Boynton/Cook Pub (1987).
Beane, J. "Dance to the Music of Time: The Future of Middle Level Education." THE EARLY ADOLESCENT MAGAZINE 2 (September 1987):18–26.
Beane, J. A MIDDLE SCHOOL CURRICULUM: FROM RHETORIC TO REALITY. Columbus, Ohio: National Middle School Association, 1990a.
Beane, J. AFFECT IN THE CURRICULUM: TOWARD DEMOCRACY, DIGNITY, AND DIVERSITY. New York: Teachers College Press, 1990b.
Cross Keys Middle School. A PLACE OF OUR OWN. Florissant, Missouri: Florissant Public Schools, 1990.
Jennings, W., and Nathan, J. "Startling/Disturbing Research on School Program Effectiveness." PHI DELTA KAPPAN 59 (1977): 568–572.
Fenwick, J. (Primary Author) Taking Center Stage: A Commitment to Standards-Based Education for California's Middle Grades Students. Sacramento: California Department of Education, 2001
"Why Middle Level Schools Are KEY to Young Adolescent Success" Westerville, OH: NMSA, 2003. [2]