Shown is the state flag of Connecticut, part of a pane of stamps showing the flags of each of the 50 states.

The flag of the state of Connecticut consists of a white baroque shield with three grapevines (each bearing three bunches of purple grapes) on a field of azure blue. The banner below the shield reads "Qui Transtulit Sustinet", ("He who transplanted still sustains"), the state's motto. The flag dimensions are 5.5 feet (1.7 m) in length and 4.33 feet (1.32 m) in width.

The Connecticut General Assembly approved the flag in 1897 after it was introduced by Governor Owen Vincent Coffin in 1895.

The design comes from the seal of Saybrook Colony when it was established in 1639. That seal depicted 15 grapevines and a hand in the upper left corner with a scroll reading "Sustinet qui transtulit". When Connecticut Colony bought Saybrook in 1644, the seal transferred to Connecticut Colony. On October 25, 1711, the governor and legislature changed the seal. They reduced the number of grapevines from 15 to three, in order to represent the three oldest settlements (Windsor, Wethersfield, and Hartford) (or possibly the three separate settlements, Connecticut Colony, Saybrook Colony, and New Haven Colony, which had been absorbed into Connecticut by that time) and rearranged the wording and position of the motto.

In 2001, the North American Vexillological Association surveyed its members on the designs of the 72 U.S. state, U.S. territorial and Canadian provincial flags. The survey found the Connecticut flag to be ranked in the bottom 25, ranked 50th out of the 72.