State Highway 320 (SH 320) is a short Texas state highway that runs from SH 53 near Zabcikville north to SH 7 west of Marlin.

It heads northeast from this junction to an intersection with Farm to Market Road 3369.

The highway continues to the northeast to an intersection with Farm to Market Road 431.

Heading towards the northeast, the highway continues to a junction with US 77.

The highway continues to the northeast to an intersection with Farm to Market Road 2027 in Lott.