Six Saudi universities have been listed among the world's top 1,000 in the Academic Ranking of World Universities (ARWU) for 2021, compared with last year when four universities in the Kingdom were included in the global ranking, also known as Shanghai Ranking. King Abdulaziz University and King Saud University secured a place among the world's top 150 universities with the former keeping its ranking in the ARWU's 101-150 category and the latter moving from the 200-251 category to the 101-150 category. King Abdullah University of Science and Technology, King Fahd University of Petroleum & Minerals, King Khaled University and Taif University been also ranked among the top 1000 institutions in the world. King Abdullah University of Science and Technology and King Fahd University of Petroleum & Minerals have kept their ranking for the second time in a row in the 201-300 and the 401-500 category respectively while the King Khaled University and Taif University have been ranked for the first time in ARWU in the 801-900 category. As a global classification body, ARWU ranks world's universities according to a set of criterion and standards, including the quality of education, the efficiency of faculty members, the outputs of scientific research, and the size of the institution.