Can I use WD-40 on a squeaky garage door?

You can use WD-40 on a squeaky garage door only if you are using the correct type of WD-40 and understand its limitations, because using the wrong type will make the problem worse. The original WD-40 in the blue and yellow can that most people have in their garage is not a long-term lubricant. It is a solvent, water displacer, and degreaser that will quiet a squeak for a few hours to a day by cleaning and adding a very thin oil film, but then it evaporates, leaving the parts drier than before and often attracting dust that forms a grinding paste. Using it repeatedly will strip away existing grease and accelerate wear on rollers and hinges. However, the WD-40 brand also makes Specialist products that are suitable, such as WD-40 Specialist White Lithium Grease and WD-40 Specialist Water Resistant Silicone Lubricant, and WD-40 Specialist Garage Door Lube. Those specialist formulas are true lubricants designed for overhead doors and are perfectly fine to use. If you have only the original WD-40, you can use it to clean dirty tracks or remove rust, but then you must follow up with a proper silicone or lithium garage door lubricant for lasting protection. For best results, avoid standard WD-40 as your primary lube.