A fire lookout tower, fire tower or lookout tower, provides housing and protection for a person known as a "fire lookout" whose duty it is to search for wildfires in the wilderness. It is a small building, usually on the summit of a mountain or other high vantage point, to maximize viewing distance and range, known as view shed. From this vantage point the fire lookout can see smoke that may develop, determine the location by using a device known as an Osborne Fire Finder, and call fire suppression personnel to the fire. Lookouts also report weather changes and plot the location of lightning strikes during storms. The location of the strike is monitored for a period of days afterwards, in case of ignition.

A typical fire lookout tower consists of a small room, known as a cab, atop a large steel or wooden tower. Historically, the tops of tall trees have also been used to mount permanent platforms. Sometimes natural rock may be used to create a lower platform. In cases where the terrain makes a tower unnecessary, the structure is known as a ground cab. Ground cabs are called towers, even if they don't sit on a tower.

Towers gained popularity in the early 1900s, and fires were reported using telephones, carrier pigeons and heliographs.

Although many fire lookout towers have fallen into disrepair from neglect, abandonment and declining budgets, some fire service personnel have made efforts to preserve older fire towers, arguing that a person watching the forest for wildfire can be an effective and cheap fire control measure.