In the United States military, stop-loss is the involuntary extension of a service member's active duty service under the enlistment contract in order to retain them beyond their initial end of term of service (ETS) date and up to their contractually agreed end of active obligated service (EAOS). It also applies to the cessation of a permanent change of station (PCS) move for a member still in military service. Stop-loss was used immediately before and during the 1990–91 Persian Gulf War. Since then, it has been used during deployments to Somalia, Haiti, Bosnia, Kosovo and after the September 11 attacks and the subsequent War on Terror.

The policy has been legally challenged several times. However, federal courts have consistently found that military service members contractually agree that their term of service may be involuntarily extended until the end of their obligated service.