Adult Qualifying Child

• The IRS may allow you to continue claiming a child as a dependent even after reaching the age of maturity. However, if she is over the age of 18, but younger than 24, and is a full-time student at the end of the tax year, the adult child can be a qualifying child. And as long as your adult child doesn't provide more than half of his own financial support, regardless of how much Social Security income she receives, and resides with you for more than half of the tax year, she qualifies as your dependent.
  
  

Child Lives Elsewhere

• You can't get around the requirement that your qualifying child dependent live with you for more than half of the tax year. However, the IRS disregards certain absences of you or the adult child from the residence. Commonly, an adult child will go away to college or university and live on campus. And even though he may spend a substantial portion of the year living outside your home, the IRS treats this as time he resides with you for purposes of claiming dependents. Other circumstances that the IRS deem a temporary absence is active military service of either one of you, illnesses that require hospital stays and any vacations that either of you take.
  
  

Non-Qualifying Child

• If your adult child doesn't satisfy the qualifying child requirements, you can still claim her as a dependent. The IRS allows you to claim any adult as a dependent if you satisfy certain requirements. When the adult child is your relative, such as a son, sibling, nephew or an in-law, the IRS doesn't require that these individuals live with you for even one day of the tax year to qualify. For all other adults who you have no familial relationship with, they must reside with you for the entire tax year. The harder requirement to satisfy is that any adult dependent cannot have income that is subject to tax of $3,650 or more per year.
  
  

Tax-Exempt Social Security

• The fact that the adult child has Social Security income will have no affect on your ability to claim him as a dependent. The reason is because the Social Security income he receives is tax exempt. However, there are times when a portion of Social Security is taxable, but this only occurs if the child has other sources of taxable income. Therefore, you only need to consider whether the adult child has other income. If not, you can ignore the Social Security income for purposes of the $3,650 requirement.