Claim Credit for Previous Years

Taxpayers who were eligible to claim, but did not claim, an additional child tax credit in previous years have three years after the due date of the return to claim it. However, the child must have a valid social security number issued by the due date of the tax return. For tax years 2025 and after, taxpayer must also have a valid Social Security number issued by the due date of the tax return. If married filing jointly, at least one of the spouses must meet this requirement.