Don't Ask, Don't Tell (DADT) was the official policy of the United States Department of Defense regarding the service of openly gay, lesbian, and bisexual individuals in the military. Implemented as a compromise during the presidency of Bill Clinton, the policy prohibited military personnel from discriminating against or harassing closeted homosexual or bisexual service members, but required the discharge of those who were openly so or whose sexual orientation was discovered through investigation. It aimed to balance the demands for inclusion of LGBTQ+ individuals in the armed forces with concerns from military leadership about unit cohesion and morale. The policy was codified in the National Defense Authorization Act for Fiscal Year 1994 and affected tens of thousands of service members, leading to over 13,000 discharges between 1994 and 2011. DADT faced widespread criticism from civil rights advocates for perpetuating discrimination and violating privacy rights, while supporters viewed it as a pragmatic interim measure.

The policy originated from President Clinton's 1993 campaign promise to end the longstanding ban on homosexual service members, but opposition from Congress and the Pentagon resulted in the 'don't ask, don't tell' framework. Issued as Department of Defense Directive 1304.26 on December 21, 1993, it took effect on February 28, 1994. Over its 17-year lifespan, DADT was challenged through numerous lawsuits, including landmark cases like Cook v. Gates (2008) and Log Cabin Republicans v. United States (2010), which ruled it unconstitutional. Advocacy groups such as the Servicemembers Legal Defense Network (SLDN) documented abuses, including witch hunts and involuntary disclosures. The policy's repeal was signed into law by President Barack Obama on December 22, 2010, as part of the National Defense Authorization Act for Fiscal Year 2011, with full implementation by September 20, 2011. Post-repeal efforts have focused on upgrading discharges and providing benefits to those affected.

DADT's legacy continues to influence discussions on military inclusion, with ongoing initiatives to address the inequities faced by LGBTQ+ veterans discharged under the policy. The Department of Defense has committed to outreach for record corrections and benefits restoration for those impacted. The policy remains a pivotal chapter in U.S. LGBTQ+ rights history, highlighting tensions between national security and civil liberties.