A department of transportation (DOT or DoT) is a government agency responsible for managing transportation. The term is primarily used in the United States to describe a transportation authority that coordinates or oversees transportation-related matters within its jurisdiction.

In the United States, the largest DOT is the United States Department of Transportation, a federal agency that oversees interstate travel and numerous other transportation agencies.

All U.S. states have their DOTs, responsible for managing and overseeing transportation, transportation-related infrastructure, and transportation safety in their respective states. They provide enforcement through DOT officers within their respective jurisdictions.

Though the term "Department of Transportation" is most associated with the United States,^{[citation needed]} the term has been used in various forms for other countries' transportation authorities.