Department of Defense Instruction 1300.28

Directive-type Memorandum-19-004, "Military Service by Transgender Persons and Persons with Gender Dysphoria", was a memorandum issued by the United States Department of Defense (DoD) prohibiting most transgender individuals from serving or enlisting in the United States Armed Forces and the DoD. The DTM took effect on April 12, 2019, under the presidency of Donald Trump, signed by David Norquist. Originally scheduled to expire on March 12, 2020, it was extended until September 12, 2020. Before it expired, it was replaced by Department of Defense Instruction 1300.28, which took effect on September 4, 2020, signed by Matthew Donovan.

The memorandum banned new applicants who have any history of medical transition treatment. Applicants with a history of gender dysphoria were presumptively disqualified unless they have been deemed stable after 36 months and willing to detransition to their biological sex.

The memorandum drew controversy from some politicians, former military officials, the transgender rights movement, and other commentators. Several National Guards refused to enforce the ban. The memorandum was a topic in the 2020 United States presidential election.

After Joe Biden was elected and sworn in, one of his first executive orders was the repeal of the Presidential Memorandum on Military Service by Transgender Individuals. On January 25, 2021, Biden signed an executive order that required the DoD to reverse the memorandum, permitting transgender people to serve in the U.S. military.