Can I claim my grandfather who lives in Mexico but I support financially?

[DoninGA]

Does he have a Social Security number or an ITIN issued by the IRS?  If not, you cannot claim him as a dependent.

[Cynthiad66]

It depends.  In addition to the information provided by, DdoninGA, there are also other requirements to qualify as a dependent.

The IRS states that only nonresident aliens who are U.S. nationals, residents of Canada, Mexico and South Korea; or residents of India who were students or business apprentices can have a qualifying dependent.

In general, a dependent is a qualifying child or a qualifying relative. Three exceptions apply.

1. An individual who is a dependent of a taxpayer is treated as having no dependents.
2. An individual who files a joint return is not a dependent if the individual files a joint return, unless the joint return is filed only to claim a refund of estimated or withheld taxes.
3. An individual claimed as a dependent must be a citizen, national, or resident of the United States, or a resident of Canada or Mexico.

You must show the SSN (or ITIN) of any dependent you list in the Dependents section of your Form 1040-NR, U.S. Nonresident Alien Income Tax ReturnPDF. If you do not include such information, certain tax benefits may be disallowed.

This link gives you additional information:  Do You Support Your Family Abroad

@davidcharcas24