Students must complete a disciplinary major offered in any department of Northwestern's schools. Students may declare the International Studies adjunct major before declaring a primary major, but the adjunct major does not by itself meet requirements for an undergraduate degree.

Students must satisfy the language proficiency requirement set by the College of Arts and Sciences, which is two years of study or equivalent proficiency. Adjunct majors are strongly encouraged to continue language learning beyond this minimum requirement, and to establish genuine competency in the speaking, reading, and writing of at least one foreign language. Students may not exercise the P/N option in foreign language courses taken to meet the Weinberg College foreign language requirement.