Today's Lone Star Flag was adopted on January 24, 1839 as the national flag of the Republic of Texas. It was first proposed in legislation introduced in the Third Congress of the Republic by William Wharton. The designer of the flag is unknown. The Lone Star Flag represents the fourth of the Six National Flags of Texas.

The flag was later adopted as the state flag when Texas became the 28th state in 1845. As with the flag of the United States, the blue stands for loyalty, the white represents purity, and the red is for bravery.

The official description of the Texas flag, which specifies the exact proportions of each of its elements, was only recently adopted by the state legislature. Accordingly,

"The state flag consists of a rectangle with a width to length ratio of two to three containing: (1) a blue vertical stripe one-third the entire length of the flag wide, and two equal horizontal stripes, the upper stripe white, the lower red, each two-thirds the entire length of the flag long; and (2) a white, regular five-pointed star in the center of the blue stripe, oriented so that one point faces upward, and of such a size that the diameter of a circle passing through the five points of the star is equal to three-fourths the width of the blue stripe."