My wife and son do not yet have their SSNs. My wife is a citizen of the UK and my son (3 yrs old in August) was born in the UK. I'm a U.S. citizen. Why they do not yet have their SSNs is a discussion for another day.
You are required to supply a Social Security Number (SSN) when claiming someone as a dependent on your tax return. Or, use an Individual Taxpayer Identification Number (ITIN) if they are not eligible for an SSN.
In the event of a time crunch (tax deadline approaching) you have two options:
- Go ahead and file (and not claim them), then later file an amended return with the SSN/ITIN information.
- Or, you can file for an extension if you expect to have their SSN/ITIN by then.
The accepted answer is fine for situations where a dependent does not yet have an SSN, but may not be appropriate for when your spouse does not yet have an SSN.
If your spouse is not yet eligible or will not become eligible to get an SSN, you apply for an ITIN when you file your taxes, not before or after filing your tax return.
Fill out your tax return just as you would if they had an SSN/ITIN, but you'll leave their SSN field blank and you'll attach Form W7 to your return, which is the application for ITIN. This means mailing in a paper return.