Military Mental Health Review Board Improvement Act - Requires any medical advisory opinion issued to a civilian board for the correction of a military record, with respect to a current or former member of the Armed Forces diagnosed while serving in the Armed Forces as experiencing a mental health disorder, to include the opinion of a clinical psychologist or psychiatrist if the request for the correction of the records concerned relates to a mental health disorder.

Requires any physician on a board for review of a discharge or dismissal of certain former members of the Armed Forces, who after deployment were diagnosed as experiencing post-traumatic stress disorder (PTSD) or traumatic brain injury, or as having a mental health disorder, to have training on mental health issues connected with PTSD or traumatic brain injury (as applicable), or special training on mental health disorders.