American System may refer to:

• American System (economic plan), an 1800s economic program of Henry Clay and the Whig Party based on the "American School" ideas of Alexander Hamilton
• American system, an informal name for the Universal Numbering System dental notation introduced in the US in the 1800s
• American system of manufacturing, a set of manufacturing methods that evolved in the 19th century in the US
• American system passenger coach or "open coach", a style of railway passenger coach first introduced in the 1800s in the US
• United States customary units, a system of measurement used in the US