It is bisected horizontally by a thin white line (a fimbriation, approximately 1/27th of the flag's height) with a dark red top and a dark blue bottom. A large, white 5-pointed star (approximately 14/15ths of the flag's height) dominates the flag and contains the city seal in buff and black.
The flag in use between 1916 and 1967 (though it was not actually produced until 1954) was a non-rectangular flag (similar to the flag of Ohio) with similar colors to the current flag. The top of the flag is red and the bottom is blue, but unlike the current flag, there is no fimbriation. The center of the flag contains the state of Texas in white with a star and the name "Dallas" marking the city's position in the state.