The Washington International School has two campuses in D.C. The primary school, pre-kindergarten through grade 5, is in Georgetown. Students eventually graduate through the International Baccalaureate Diploma program proficient in at least two languages, beginning with French or Spanish language instruction in pre-kindergarten.

Children in the primary school learn mathematics, science and technology, languages, social studies, arts, and personal, social and physical education in two languages. A quarter of the student body is made up of American citizens; another quarter of students are non-U.S. citizens; the other half is made up of students with multiple citizenships. An application process is required for entrance.