The Department for the Protection of Public Safety and Order, usually called the Guard Department and commonly abbreviated in modern English sources as the Okhrana was a secret police force of the Russian Empire and part of the police department of the Ministry of Internal Affairs (MVD) in the late 19th century and early 20th century, aided by the Special Corps of Gendarmes.

Secret police are police, intelligence, or security agencies that engage in covert operations against a government's political, religious, or social opponents and dissidents. Secret police organizations are characteristic of authoritarian and totalitarian regimes. They protect the political power of a dictator or regime and often operate outside the law to repress dissidents and weaken political opposition, frequently using violence. They may enjoy legal sanction to hold and charge suspects without ever identifying their organization.