Spirit Worship is as old as mankind itself. Today, many of the old animistic beliefs are intertwined with Buddhism. This has helped some animistic traditions survive in Thailand.
One which is practiced by almost every Thai is the Spirit House. They are seen in a prominent spot outside every business, hotel, restaurant and bar, on the grounds of Buddhist temples, outside caves, and many other places.

Most importantly, there is a Thai Spirit House built in the yard of every home. The purpose of the Spirit House is to provide shelter for the spirits, who would otherwise reside in the heavens, caves, trees, cliffs, waterfalls or other natural surroundings. According to folklore, the spirits themselves are neither good nor evil, but just finicky and mischievous. They demand respect from humans and are capable of disastrous interferences if they don’t get their way. The style of Spirit Houses can be simple as a typical Thai-style shelter, or as elaborate as a Thai palace. This depends on two factors: which spirit the person wishes to invite and how much one can afford for the spirit house.
Construction itself is a specialized field and only an expert Spirit House builder would be considered. His responsibility, in addition to construction, is to be familiar with all the necessary rituals involved so that the invited spirit will find it an acceptable earthly abode.

The houses are finished with statues, small figures, or other symbols being placed inside. In addition, there may be various animal figures, such as elephants. Outside, around the balcony that usually surrounds a spirit house, incense holders, candle sticks, and vases for flowers are placed.
The primary spirits of interest to Thais are called the Guardian of the Houseand the Guardian of the Gardens. They are so frequently consulted with and prayed to that they have permanent spirit houses built for them.

The Guardian of the House is the spirit that watches over and protects the home and helps in business matters. More often than not in Thailand, the business and the home are in the same location.

The Guardian of the Gardens watches over and protects the natural surroundings, yards, gardens and orchards. There is a separate spirit for rice fields, so he should not be mistaken for a spirit protecting all of agriculture. Nature, flowers, plants and fruit are very important to the Thais. Offerings to a spirit house can be nearly anything. The traditional offerings include flower garlands, betel leaves, bananas, rice, chicken, duck, and a wide range of other edibles and nonedible. Candles are often used, while incense is usually lit daily in front of Spirit Houses.

The Spirit House is one of the most fundamental features of Thai life, even today, capturing the attention of both locals and tourists. And while devotion to Buddhism most often shows itself in rituals within a temple, Thai devotion to the spirits, and especially the guardians of the land and house, most often takes place right in their own front yards.