The automated grass cutter is a sickle mower that is driven along a rail in order to autonomously cut grass. The automated grass cutter places a rail of an undefined length or track, which is supported via fence posts. A drive wheel system is engaged onto the rail in order to drive the sickle grass mower along the rail. The fence posts may include a fence rail spanning between consecutive fence posts. The sickle grass mower extends laterally from the rail, and relies on a drive motor to drive the drive wheel system and sickle mower along the rail. The sickle mower includes a reciprocating blade that reciprocates back and forth via movement of guide wheels.