Military Justice Transparency Act This bill requires the Department of Defense (DOD) to take specified actions to further detect and address racial, ethnic, and gender disparities in the military justice system. Specifically, DOD must require each military department to record the race, ethnicity, and gender of the victim and the accused for each investigation of an offense under the Uniform Code of Military Justice (UCMJ); record the race ethnicity, and gender of each individual against whom non-judicial punishment is imposed under the UCMJ and set forth information separately for each type of non-judicial punishment imposed; record the race, ethnicity, and gender of each individual convicted in a court-martial and set forth such information separately by the type of court-martial, the offense involved, and the case outcome; and publish specified data in the annual military justice reports. Not later than 30 days after the date on which the annual military justice reports for FY2022 have been submitted, DOD must brief Congress on its strategy to detect and address racial, ethnic, and gender disparities in the military justice system. The Government Accountability Office (GAO) must report on its findings regarding racial disparities in the military justice system, any steps being taken by DOD to address such disparities, and the status of implementation by each military department of recommendations set forth in the GAO report titled Military Justice: DOD and the Coast Guard Need to Improve Their Capabilities to Assess Racial and Gender Disparities (GAO-19-344).