My niece removed my name from my 92-year-old mother's checking and savings accounts. Is this legal without my permission?

This is true unless of course they can intimidate people at the bank like my MIL who often forged my wife's signature on and off of CDs ect. until that was put an end to. My MIL should be in jail for a whole list of reasons.

If you completed a signature card with the bank, you CANNOT be taken off the account unless you die or go to the bank to do it yourself. Contact the bank to see exactly what happened. If you suspect elder abuse by your niece then turn her into the police ASAP before she spends money she cannot return.

Stressed is right. You can't just take someone off the acct w/out that person being notified. Unless she closed out the entire acct and opened a new one. If that is the case you will have to question yur mother. Also why is so many people of her acct. There shud only be one person taking care of mom's affairs??

My brother and I have a joint acct with my dad. No one can be removed from our acct without the signature of the person being removed. Don't know if that is our bank's rule or the law, but all banks I have dealt with follow this policy.

Is your Mom mentally competent to sign off on this? If not, check into the whole situation and find out if she even knows what she did. If the niece coerced her into doing this, then you can get it overturned. Mom has dementia and we make sure that everything is done in front of witnesses.

It depends on what relationship you have with your mother and how she is directed you to handle any financial affairs.
Is this a joint account or are you just a "signer" on the account? Do you have Power of Attorney? What is the reasoning for having your removed?
Your niece should not be able to make changes unless your mother directed her to do it and your Mom signed off on it.