Why Is My Cat's Jaw Quivering?

Does she make a strange noice when she does that too? Its called chattering. Most cats do it when they see something they want but can't have, for instance a bird. Its extremely commen among cats, although if he is doing it at odd times. Like in front of his dinner, he could be trying to tell you something. Keep a close eye on him and check for any changes in personality, eating, sleeping, or going to the bathroom. Also, check in his mouth to see if he has any chipped teeth, if he does it could be causing him pain to eat.

I think there is some change in your home that is making your cat upset. Well if you are sure that there is nothing like that then still pay more attention to your cat and give it more time daily. There is a disease known as Toxoplasmosis. In this disease cats show brain disorders like lack of coordination, circling, constricting pupils, personality change and other central nervous system abnormalities and jaw quivering etc. You cannot do anything if your cat is suffering from this disease. All you have to do is take it to vet and give it medicine regularly as prescribed by its vet.

Cats quiver their jaw if they are hunting something tiny like a fly
if that's not so then it might have something stuck in its teeth or sometimes flat pieces of bones can lodge on the surface of the upper gums and that might be irritating your cat