File IRS Form W-7 with proof of identity/foreign status (passport), your I-20 and I-94, plus a letter showing why you need an ITIN (e.g., taxable scholarship/stipend or tax-treaty claim). Submit it with your Form 1040-NR at tax time, or apply in person through an IRS Taxpayer Assistance Center or a Certified Acceptance Agent (CAA).

If you’re eligible for an SSN (on-campus job, CPT/OPT), get an SSN instead; you won’t qualify for an ITIN. No U.S. income? You typically file Form 8843 only and don’t need an ITIN.

Tips: use original or issuing-agency–certified documents (CAAs can verify passports), keep copies, and expect several weeks for processing.