Locate the squeaky garage door components. Listen closely as the door opens and closes to determine which components are squeaking.
Spray the squeaky moving parts with a lightweight spray oil. Raise and lower the door while spraying the oil into the component so the lubricant works its way into all the way into the device.
Spray oil into the rest of the components of the garage door containing moving parts. They may not squeak today but a little preventive maintenance may prevent those problems down the road. Spray each hinge, roller and the lock mechanism with light oil.