Instructions and logic provide memory key protection functionality. Embodiments include a processor having a register to store a memory protection field. A decoder decodes an instruction having an addressing form field for a memory operand to specify one or more memory addresses, and a memory protection key. One or more execution units, responsive to the memory protection field having a first value and to the addressing form field of the decoded instruction having a second value, enforce memory protection according to said first value of the memory protection field, using the specified memory protection key, for accessing the one or more memory addresses, and fault if a portion of the memory protection key specified by the decoded instruction does not match a stored key value associated with the one or more memory addresses.