My child and grandchild lived in an apartment I leased and paid. My name is on the lease and I provided at least 90% of their support. Is my grndchild a qualifying child?

[TomK2023]

It depends.

You can claim a child, relative, friend, fiancé(e), and so on as a dependent on your 2024 taxes as long as they meet the following requirements:

Qualifying child:

They're related to you.
They aren't claimed as a dependent by someone else.
They're a US citizen, resident alien, national, or a Canadian or Mexican resident.
They aren’t filing a joint return with their spouse.
They're under the age of 19 (or 24 for full-time students).
There's no age limit for permanently and totally disabled children.
They lived with you for more than half the year (exceptions apply).  Pub. 501 Dependents, Standard Deduction, and Filing Information (pgs. 18-19)
They didn't provide more than half of their own support for the year.
 

Qualifying relative:

They don't have to be related to you (despite the name).
They aren't claimed as a dependent by someone else.
They're a US citizen, resident alien, national, or a Canadian or Mexican resident.
They aren’t filing a joint return with their spouse.
They lived with you the entire year (exceptions apply).
They made less than $5,050 in 2024.
You provided more than half of their financial support.

When you add someone as a dependent, the program will ask a series of questions to make sure you can claim them. There may be other tax benefits you can get when you claim a dependent.

For more information, read TurboTax article: Rules for Claiming Dependents on Taxes