Walling is an interrogation technique where an interrogator forces a prisoner to stand with his heels against a fake wall, and then slams the prisoner into the wall, creating a loud noise as the wall deflects under the pressure. This creates disorientation and fear, as the prisoner may worry about slamming through the wall and can experience a ringing sensation in his ears from the noise. This practice is considered torture by many international legal authorities and is not legal in some countries. Others defend it, arguing that it does not put the prisoner in any immediate danger.

Simply standing with heels against the wall can be uncomfortable for prolonged periods of time, and interrogators may use this as a stress position, ordering the prisoner not to move. When the interrogator combines this with pushing the prisoner into a wall the prisoner thinks is real, it can create considerable psychological stress in addition to physical discomfort. Some prisoners report having collars or towels wrapped around their necks to support the cervical spine, preventing whiplash. Interrogators may argue that looking out for prisoner safety during walling procedures is an indicator that this practice is not torture.

This technique can expose prisoners to injuries, even if their necks are protected. It is possible to fracture bones by pushing someone into a wall hard enough, and prisoners typically end up with heavy bruising, especially along their shoulder blades. The walling sessions may be combined with sleep deprivation, bright lights, and loud noises, which can increase the sense of disorientation and expose people to mental health complications like psychosis or depression.

In regions where this practice is not legal, prisoners can report walling to welfare advocates and international organizations, if they can access representatives of these groups. These groups can conduct an investigation into interrogation practices at the prison facility, and the result may be an exposé that forces the prison to revise its practices. These groups can also mandate the use of observers in interrogation rooms to make sure personnel abide by international law.

When a government does not ban walling or explicitly authorizes the practice in particular facilities, prisoners generally have no recourse for filing complaints. They can take notes on prison conditions and seek assistance from an attorney who may argue that while individual practices may be legal, combined, they constitute torture by creating emotional and physical distress or the threat of permanent injuries.