Why cant i claim her as a dependent? she lives in Mexico has no us income or other people claiming her?

[DoninGA]

Who are you trying to claim?  Is it a relative?

[landtechland]

Can I claim my half brother who is minor US citizen that lives in Mexico and I support.

[landtechland]

yes

[Vanessa A]

It depends.  

You would not be able to claim him as a qualifying child if you lived in the US and he lives in Mexico unless you lived with him for more than 6 months during the year.

You may be able to claim him as a qualifying relative, even though he lives in Mexico, which allows you to claim  the $500 Non-Refundable Other Dependent Credit if he meets all the criteria.  

To claim someone as a Qualifying Relative, they must be:

• Your child ( including step children, adoptive children and foster children) or a descendent of them
• Your sibling (including half siblings) or a child of your sibling or a sibling-in-law
• Your parent or grandparents, including step parents and in laws
• Not a qualifying child of another taxpayer
• Someone that you provided over half of their support for during the tax year
• Has less than $5,050 in income (not counting social security)