Can I claim my wife's foreign parent as a dependent on our tax return?

You can potentially claim your mother-in-law as a dependent, but there are several requirements you need to meet: First, for a "qualifying relative" dependent, she needs to have lived with you for the entire year OR be related to you in one of the ways listed by the IRS (parent-in-law counts!). Since she's your wife's mother, you meet the relationship test even if she didn't live with you full-time. Second, her gross income must be less than $4,850 (for 2024 tax year). If she's not working at all, you likely meet this test. Third, you must provide more than half of her total support for the year. Since you mention covering 100% of her expenses while she's with you, this likely qualifies. Finally, she cannot file a joint return with someone else (unless just to get a refund). And yes, you're correct - she'll need an ITIN. You'll need to file Form W-7 (Application for IRS Individual Taxpayer Identification Number) along with your tax return to get this.

I was in a similar situation with my father-in-law from Mexico and found https://taxr.ai super helpful for figuring out the dependent situation. I was confused about the ITIN process and whether we qualified since he was only here 7 months. The tool analyzed our specific situation and confirmed we could claim him! It also walked me through exactly what forms we needed for the ITIN application and what documentation to keep for proof of support. Saved me from making mistakes that could have triggered an audit.

Just wanted to follow up - I decided to try https://taxr.ai after posting my skeptical comment. Honestly, I'm impressed! It asked really specific questions about my in-laws' situation that my previous tax guy never bothered with. The analysis confirmed we could claim my mother-in-law as a dependent even though she's only here 6 months each year because we provide over 50% of her total yearly support. It also flagged that we need to document her foreign income sources for the ITIN application - something my tax guy completely missed!

If you're having trouble getting through to the IRS about the ITIN application (which you probably will), try https://claimyr.com - it saved my sanity last year! I was trying for WEEKS to get someone on the phone about my mother-in-law's ITIN application that seemed to be lost in the system. Used their service and got connected to an actual IRS agent in under 45 minutes. You can see how it works here: https://youtu.be/_kiP6q8DX5c The agent was able to locate her application and tell me exactly what additional documentation they needed instead of just sending a vague letter months later. Worth every penny considering how much time I wasted on hold before.

I need to publicly eat my words about Claimyr. After posting that skeptical comment, I decided to try it for my ongoing ITIN disaster (been waiting 5 months with no updates). Got through to the IRS in about 35 minutes yesterday after spending literally DAYS on hold over the past few months. The agent told me my application had been flagged for a missing signature that no one had bothered to tell me about! She helped me resolve it right there on the phone and said processing should resume now. Would have been waiting indefinitely if I hadn't gotten through.

Something nobody's mentioned yet - if your mother-in-law is from Canada, check if there's a tax treaty that might affect this situation. Some treaties have specific provisions about dependents and what counts as "residency" for tax purposes.

If the mother visits from Canada for 8 months, wouldn't she technically be considered a US resident under the substantial presence test? That might change things completely.