Many flags in Thailand were originally created for various religious ceremonies. Later on, flags were used for personal purposes, hung around homes or places of business, paraded by the armed forces, used to identify ships at sea, and generally used to symbolize the country. There are three main categories of flags which one can see suspended from poles or lines:

1. Strings of Pennants These flags are triangular in shape, and can be made from cloth, paper, tree leaves or metal. Many flags are attached to a straight line or long string. The base of each flag is attached to the line, while the pointed tapered end hangs downwards. Originally this type of flag was used for religious ceremonies, mostly as a substitute for the sacred white cord used to connect houses and buildings to the auspicious site of the ceremony. Currently, these hanging pennants are much in evidence at fairs and festivals, and even social gatherings, because their colors brighten up the surroundings and lend a festive air to the occasion.

2. Banners This flag is rectangular in shape and usually very long. It can be made from cloth, paper, thin wooden strips, silver, zinc plate, or combinations of these. Many have each piece decorated with hand-drawn or painted depictions of animals ranging all the way from caterpillars to crocodiles. The pictures of animals or other subjects vary according to the theme of the occasion. For example, the procession of a "Kathin ceremony"may be transported by boat; therefore a crocodile motif would be most appropriate.

It is believed that the ancient "Mon" people, an ethnic group originating in present-day Burma who migrated to north and south Siam, invented this type of banner. These banners are usually hung on a single bamboo pole, which is inserted in the top of a conical-shaped sand pile, or hung on a pole topped with a carved swan.

These banners are still very popular in northern Thailand, and can often be seen along the roadside near wats (Buddhist temples) at the time of various religious holidays or festivities. Northern people refer to these banners as "toong". This is actually the root word for"thong"which means "flag" in the Thai language. Many people in parts of the North believe that the toong banner represents a stairway to heaven for the soul to cross, and have one in their homes to prepare for their entry into the next world. These banners are very interesting with their large variety of symbols, colors, thickness and lengths.

3. Large Flags These may be square, rectangular or triangular in shape. In ancient times, this type of flag was used in warfare by armies and navies alike. They were also used to identify the country of origin of cargo ships. Later, these flags were used to decorate places and especially government buildings, and then became the standard for national identity. It is interesting to note that the triangular flag is used to symbolize victory and is called: "thongchai"("victory flag"). Armed forces used this flag at the front of their lines, hoping to inspire their foot soldiers onward to victory. Historically, the Siamese flag first appeared in the Ayuthaya period. During the reign of King Narai the Great, a ship from France sailed to the mouth of the Chao Phraya River to the south of yet-to-be-born Bangkok. While the ship was approaching a lighthouse, the Siamese military raised the Dutch flag in greeting and as a gesture of friendship, as the Siamese did not yet have a flag of their own. The Siamese soldiers did not realize that France and Holland were engaged in a serious conflict at the time, and the French undoubtedly misread the signal. The quick-thinking Siamese then raised another flag, solid red in color, to stop the French from invading Siamese territory. From that day, the first Siamese national flag was red. This red flag was also flown on cargo chips from the Ayuthaya, Thonburi and early Rattanakosin periods.

Aware that the red flags were being used both for commerce and government agencies, King Rama I wanted to make a distinction between the two. Therefore he added a white wheel design to the middle of the red flag to be used by the government and on royal ships. The private sector continued to fly the plain red flag. Even today, after all these years, plain red flags are still in use on cargo ships.

During the period of King Rama II, there was confusion between Siamese ships and vessels of British Singapore, both of which flew a plain, red flag. To resolve this problem, King Rama II added a white elephant to the center of the white wheel. The white elephant symbolized the enormously auspicious events of three white elephants being found during his reign on the throne.

As more and more contacts were made between the west and Siam during his reign, King Mongkut (Rama IV) wished to establish a genuine national flag. He removed the white wheel and enlarged the size of the white elephant figure in the middle of the flag. Since B.E. 2398, cargo ships from Europe and America have arrived in Bangkok, and foreign governments have been given permission to build embassies and consulates. Flags of each consulate were allowed to be displayed from flagstaffs. It was at about this same time that the modified Siamese flag was instituted.

In B.E. 2460, the beginning of World War I, King Vajiravuth (Rama VI) envisioned that Siam would become well known and gain respect if the country declared war against Germany, Austria and Hungary. The flag motif was then changed from a solid red color with a white elephant, to a design of red and white stripes. Initially, his design was five stripes, three red stripes alternating with two white stripes. Later Thailand's flag became "tri-rong"or three colored, as it is today. The outer red stripes stand for the country's unity; the two white stripes refer to purity of religious freedom (to practice Buddhism, Islam or Christianity), while the blue stripe, the heart of the flag, represents the Monarchy.