Since it was established by his Royal Highness , Prince Abdulla Bin Mosaad Bin Abdul Aziz AlSaud and Mrs. Tomader M. Ayad in 1998., O.I.S has enjoyed a reputation that qualified it to gain the trust of parents as well as the accreditation of respected educational organizations .
In the year 2000-2001, the school got the approval of David Game College Group as an educational institution to teach the British curriculum to 645 students registered up to grade 9 .In 2003-2004, the school transferred premises with a total number of 932 students. By March 2005, the school has been inspected by the CITA accredited visit for Quality Assurance Review .The visit has resulted in accrediting the school by the committee , a fact that urged all the school staff to exert more efforts not only to keep what they gained but also to achieve more .Then, opening classes of senior grades, 10 to 12 , in the year 2006-2007 encouraged so many students to join the school that the total number increased from 2385 in 2009-2010 to more than 3000 in 2012-2013. The school was re- accredited by the AdvancED in 2011 for 5 years based on the new standards of accrediting the American schools. Also , one important breakthrough that the school has achieved is that it has become an accredited SAT Test Center since October 2013 .