The Assumption Cathedral is the main Roman Catholic church of Bangkok. The original building at this place was the brainchild of French missionary Father Pascal in 1809, and completed in 1821. Throughout the second part of the 19th century, the area surrounding the church played an important role for French Christian missionaries arriving in Bangkok. It is near the Oriental Hotel and the French Embassy in an area that still captures somewhat of its French history. The current church dates from the 1910s, when the building was completely reconstructed in a Romanesque style. It was heavily damaged by bombing in World War II, but was restored after extensive repairs. Its rectangular structure and red brick exterior makes it stand out from the dull white surroundings. Its interior is spacious with a high ornate ceiling. Pope John Paul II visited the church in 1984, showing the prominence of the church in the Roman Catholic community of Thailand. The only religious service in English is held Sundays at 10:00.

The Assumption Cathedral (Thai: อาสนวิหารอัสสัมชัญ) is the principal Catholic church of Thailand, located at 23 Oriental Avenue, New Road, in the Bang Rak District of Bangkok. It is the main church of the Archdiocese of Bangkok. The cathedral hosted both of the papal visits to Thailand: Pope John Paul II in 1984 and Pope Francis in 2019.