A parecclesion (Greek: παρεκκλήσιον, translated as "Chapel," romanized: parekklesion, lit. 'side-church') is a side mortuary chapel found in early Byzantine churches.

The parecclesion was often used for ceremonial and funerary purposes, which often consisted of services performed before burial, as well as services performed after to commemorate the individuals who have departed. This was a significant process that helped guide the community and helped the community understand the passage of the departed. The ceremonies were arranged as soon as a person would pass away.

Many characteristics form a parecclesion, for instance, the church in which it is located, is an architectural aspect, most significant for its exterior and interior design. The similarities of parecclesions are how they are an additional chapel separate from the main church, which is why it is labeled as 'side chapel.' The parecclesion holds an important role in unifying the human and the Divine. Most churches are sacred places considered to be a “Heaven on Earth.” Because of its exterior and interior design, such as the inclusion of high ceilings and the iconography of religious figures depicted on the walls, it helps maintain a divine experience. They are typically adorned with Frescos portraying religious figures, while addressing various themes such as resurrection, salvation, hope, Life after death, etc. These depicted scenes show the viewer what to expect at the end of time.

There are two examples of existing parecclesions:

The Roman Empire, also referred to as the Byzantine Empire, began in 330 B.C. During this time, Constantine the Great, who was the Emperor of the Byzantine Empire, decided to convert to Christianity, which expanded Christianity throughout his empire. Byzantine art has a close association to the ceremonies that were being executed inside the pareclessions, religious beliefs were now being manifested inside the parecclesions. Some of the artistic creations included in the parecclesion were- Mosaics and frescos. During the Byzantine Empire, most art with in the pareclessions centered religious icons, which is why religious figures are commonly found throughout the interior of Byzantine churches.

Byzantine art is divided into three periods because of its diverse range of art styles throughout the years. Early Byzantine art (c. 330- 750), Middle Byzantine art (c. 850-1204), and late Byzantine art (c.1261-1453). Early Byzantine art was created during the rule of Emperor Constantine, who adopted Christianity. Religious Icons such as the Virgin (Theotokos)and Child between saints (Theodore and George), as well as Jesus Christ, are depicted often. These illustrations of religious figures served a spiritual purpose, which was to encapsulate a heavenly realm in these structures Middle Byzantine art was an era of the revitalization of classical forms and motifs. The material gold (leaf) was common during this period. Finally, Late Byzantine art consisted of religious iconography and utilized symbolic imagery. The incorporation of gold continued, but was more common during middle Byzantine art.

The Chora Church or Kariye Mosque (now a museum) is located in Istanbul, Turkey. It is a prime example of Byzantine architecture which is also known for its incorporation of Byzantine art. It was once a church that was a part of a Monastery of Byzantine. The Chora holds a parecclesion rebuilt by Theodore Metochites, a wealthy official, who added the parecclesion to the Chora from 1316 to 1321 which was the fifth phase of construction in the church.

Like previously mentioned, the parecclesion was meant to serve as a chapel for ceremonial and funerary purposes. They took place in the parecclesion under the dome of the west bay, and were often done before burial and after as well to commemorate those who passed. The rituals followed a specific procedure. This process included washing and dressing the body of the deceased individual, and then placing the body inside the coffin where it then would be taken to the parecclesion. Once there, a prayer is read over the coffin, as a way to protect the soul of the deceased individual during its spiritual transition. The services and rituals at the parecclesion could be done without disturbing those attending for regular use of the church and the Narthexes since there it is an additional chapel of the church. Theodore Metochites added the parecclesion and was buried in that chapel once he passed in c.1332. An additional eight tombs were added after the place was decorated.