A cram school (colloquially: crammer, test prep, tuition center, or exam factory) is a specialized school that trains its students to achieve particular goals, most commonly to pass the entrance examinations of high schools or universities. The English name is derived from the slang term cramming, meaning to study a large amount of material in a short period of time. The word "crammer" may be used to refer to the school or to an individual teacher who assists a student in cramming.

Cram schools may specialize in a particular subject or subjects, or may be aligned with particular schools. Special cram schools that prepare students to re-take failed entrance examinations are also common. As the name suggests, the aim of a cram school is generally to impart as much information to its students as possible in the shortest period of time. The goal is to enable the students to obtain a required grade in particular examinations, or to satisfy other entrance requirements such as language skill (e.g.: IELTS). Cram schools are sometimes criticized, along with the countries in which they are prevalent, for a focus on rote learning and a lack of training in critical thinking and analysis.

Cram schools are referred to largely as "coaching colleges" or "tuition centres". They are used primarily to achieve the necessary results for the entrance exam for highly competitive selective schools in New South Wales and Victoria. They are also used extensively in English, mathematics and science courses for the Higher School Certificate, Victorian Certificate of Education, and other high school subjects in the final years of schooling.

In Bangladesh, cram schools are known as "coaching centers" and in some cases, "tutorials". Most cram schools provide help for admission tests of public universities and medical colleges like BUET, CUET, RUET, KUET, Universities of Dhaka, Chittagong, Rajshahi and Jahangirnagar, medical colleges etc., and public examinations like PSC, JSC, SSC, and HSC. There are also some variants which have entered the market of ever-increasing help seekers. For example, cram schools now also prepare students for language tests like IELTS and TOEFL, aptitude tests like GRE, GMAT, SAT, and so on. In recent years, cram schools have also been extended to the tests for government civil services like BCS Examination.

Cram schools are called "Cursinhos" (lit. Little Courses) in Brazil and are attended by students who will be taking a vestibular exam to be admitted into a university.

Cram schools are called "Preuniversitarios" in Chile, and are attended by students before taking PAES (Superior Education Entrance Test) in order to get onto undergraduate studies.

Buxiban (traditional Chinese: 補習班; simplified Chinese: 补习班; pinyin: Bǔxíbān) are cram schools located in China. They are related to the phenomenon of buke, which is extra study for the improvement of students’ academic performance in National Higher Education Entrance Examination (commonly known as Gaokao). They exist due to the importance of standardized exams, such as:

China has a test-driven system. Education departments give entrance examinations to sort students into schools of different levels. Examinations like the National Higher Education Entrance Examination (Gaokao) are vital, deciding the academic future of the participants. This education system cultivated the cramming style of teaching. Schools and teachers usually regard grades to be the primary goal. This sometimes leads to teachers imparting exam skills instead of knowledge and inspiration. But as the population of students decreases each year and admission to domestic universities expands, the pressure of the Entrance Exam has been reducing.