The school follows the philosophy of the "Basic School" which projects the school as a social organization with importance given to academic achievement, character development, and community responsibility. The curriculum is similar to that of a school in the U.S. with instruction in Spanish only in language and social studies for those fluent in the language. Spanish is taught as a second language to those who need this instruction. The high school program is U.S. college preparatory with a parallel program for those who want to study at universities in El Salvador. The school is a member of the International Schools Association of Geneva, Switzerland. It is also accredited by the Salvadoran Ministry of Education.

The International School of San Salvador was founded in 1979 by Chester and Nora Stemp, the present proprietors. The school offers a Kinder-12th grade program of studies modeled on the U.S. educational system and incorporates the requirements of the Salvadoran Ministry of Education. Located in an urban residential area, this small private school meets the needs of students of various nationalities, cultures, and linguistic backgrounds. The school is a member of the following organizations:
AASCA - Association of American Schools in Central America.
ISA - International Schools Association; Geneva, Switzerland.
ISSE - International School to School Experience; Philadelphia, Pennsylvania.
NASSP - National Association of Secondary School Principals.
NASC - National Association of Student Councils.