Sanjak-bey, sanjaq-bey or -beg (Ottoman Turkish: سنجاق بك, lit. 'lord of the standard') was the title given in the Ottoman Empire to a bey (a high-ranking officer, but usually not a pasha) appointed to the military and administrative command of a district (sanjak, in Arabic liwa’), hence the equivalent Arabic title of amir liwa (أمير لواء ’amīr liwā’) He was answerable to a superior wāli or another provincial governor. In a few cases the sanjak-bey was himself directly answerable to the sultan in Constantinople.
Like other early Ottoman administrative offices, the sanjak-bey had a military origin: the term sanjak (and liva) means "flag" or "standard" and denoted the insigne around which, in times of war, the cavalrymen holding fiefs (timars or ziamets) in the specific district gathered. The sanjakbey was in turn subordinate to a beylerbey ("bey of beys") who governed an eyalet and commanded his subordinate sanjak-beys in war. In this way, the structure of command on the battlefield resembled the hierarchy of provincial government.