Would I know if someone else tried to claim my dependant?

[HelenC12 · Accepted solution]

Yes, you'd  know if your your dependent claimed themselves (if they had a a job and filed an income tax return) or if someone else claimed your dependent.

• If you e-file your tax return and it gets rejected, the rejection will be "A dependent on your return has already been claimed (or claimed themselves) on another return".

See:  What if somebody already claimed my dependent?