According to IRS.gov.

Basic Qualifying Rules

To qualify for the EITC, you must:

• Show proof of earned income
• Have investment income below $3,650 in the tax year you claim the credit
• Have a valid Social Security number
• Claim a certain filing status
  • To qualify for the EITC, you must file your tax return using one of the following statuses:
    • Married filing jointly
    • Head of household
    • Qualifying widow or widower
    • Single

    You can’t claim the EITC if your filing status is married filing separately.

• Be a U.S. citizen or a resident alien all year

Special Qualifying Rules

The EITC has special qualifying rules for:

• Military members
• Clergy members
• Taxpayers and their relatives with disabilities

If you’re unsure if you qualify for the EITC, you can use IRS Qualification Assistant.

Claim the EITC Without a Qualifying Child

You are eligible to claim the EITC without a qualifying child if you meet all the following rules. You (and your spouse if you file a joint tax return) must:

• Meet the EITC basic qualifying rules
• Have your main home in the United States for more than half the tax year
  • The United States includes the 50 states, the District of Columbia and U.S. military bases. It does not include U.S. possessions such as Guam, the Virgin Islands or Puerto Rico
• Not be claimed as a qualifying child on anyone else’s tax return
• Be at least age 25 but under age 65 at the end of the tax year (usually Dec. 31)

You are not eligible to claim the EITC if:

• Your filing status is married filing separately
• You filed a Form 2555 (related to foreign earned income)
• You or your spouse are nonresident aliens.