Which African country's flag has a yellow star in the upper hoist corner?

The Central African Republic’s flag has a yellow star in the upper hoist corner, so the Central African Republic is the single canonical answer.

The flag was adopted on 1 December 1958, while the territory was still moving from French colonial rule toward independence. It consists of four horizontal bands—blue, white, green, and yellow—crossed through the center by a vertical red stripe. A single yellow five-pointed star appears in the upper-left corner.

Designer Barthélemy Boganda intended the colors to connect African identity with France. Blue and white represented France, while green and yellow represented Africa; the red stripe symbolized the blood and unity linking them. The star is commonly described as the star of independence, expressing hope, progress, and African unity.

The flag can be confused with neighboring countries’ flags because Chad uses blue, yellow, and red vertical bands, while the Democratic Republic of the Congo has a blue field with a yellow star. Neither has the Central African Republic’s distinctive four-color horizontal design crossed by red.