The Missouri Territory, and later the state, adopted the name form the Missouri River. The river was originally named for the Missouri Indians who lived along the banks.

The flag has one red, white, and blue band for the background which represents Missouri's French heritage as it was part of the Louisiana Purchase from France. Centered on this background is the Missouri State Seal. The seal is made up of a blue circular band in the center surrounded by 24 white stars intended to represent Missouri as the 24th state to enter the Union. The two grizzly bears on either side represent bravery and strength. A knight's helmet and another 24 stars are found above the bears. The motto, "UNITED WE STAND, DIVIDED WE FALL" encircles the inner circle of the seal. Beneath the bears is a yellow ribbon with, "SALUS POPULI SUPREMA LEX ESTA" which in Latin means, "Let the welfare of the people be the supreme law". The Roman numeral MDCCCXX is under the two bears and represents the year of the Missouri Compromise which enabled it to become a state within the union.