Joint Tenancy refers to ownership of property by two of more people. This protects property from probate as deceased’s portion of ownership passes to other joint tenant(s). You might think that a will would override joint tenancy laws. Not so. Since the transfer of a jointly held asset essentially occurs automatically upon death, it’s out of the estate before the will is even triggered.
Imagine two cousins own a piece of property as joint tenants. When one dies, his will states that his wife should inherit all of his assets. But because the property is owned in joint tenancy, the surviving cousin (Joint Tenant) owns the entire property; the surviving spouse has no claim on the property! This and other problems of joint tenancy can be avoided with a good estate plan.