Known in Spanish as the “Bandera de Espana”, the current Spanish flag has been in use since 1978, after the end of the Franco regime, though its origin can be traced to the Naval Ensign of 1785, Pabellon de la Marina de Guerra under Charles III of Spain. One of the articles of the Spanish Constitution of 1978 states that the Spanish flag should consist of three horizontal stripes: two red stripes that appear on either side of a yellow stripe in the center. The yellow strip must also be twice as wide as each red stripe.

Further descriptions of the Spanish flag are specified in Rule number 3 of the Royal judgment number 1511/1977.This rule states that the Spanish coat of arms will be located at 2/5 of the width and will appear on both sides of the flag; if the flag is of regular proportions (length equal to 3/2 of width), the coat's axis will be placed at a distance from the hoist equal to half of the flag's width. If the flag's length is less than normal or the flag is square-shaped, the coat of arms will be placed at the center of the flag. The Spanish flag with the coat of arms is the one that is in regular use, even though another constitutional version exists that does not feature the coat of arms.

Act 39/1981 provides rules the use of the Spanish flag. It states that the flag can only be flown horizontally from public buildings, private homes, businesses, ships, town squares, or during official ceremonies. Within the geographical boundaries of Spain, the flag must be flown only from sunrise to sunset, but outside of Spain, the flag must be flown for 24 hours. At night, the flag must be properly lit. In order to indicate mourning, the flag can be at half-staff, that is lowered to the pole’s one-third position, or, if the flag is permanently fixed to a staff, then, a black ribbon, 10 centimeters wide, must be attached to the mast so that the ends of the ribbon reach the bottom of the flag.

The flag may be used to cover the coffins of government officials, soldiers, and other persons as determined by the king; before burial the flag must be folded and presented to the next of kin. The flag must never be soiled or damaged in any way. Correct order must be followed while flying the Spanish flag with other flags within Spain. The Spanish flag must precede, with the flags of foreign states, the flag of the European Union, international NGOs, flags of the Autonomous Communities, city flags and others following. The foreign flags used alongside the Spanish flag are placed according to their spellings in the Spanish language. An unofficial version of the Spanish flag exists with a bull superimposed on it. This flag has become immensely popular at sporting events featuring Spanish teams and players.