The Tomb of the Koguryo Kingdom (also known as the Tomb of King Tongmyong or the Mausoleum of King Tongmyong) is an ancient burial complex located in Pyongyang, the capital city of North Korea. It was built during the Koguryo Kingdom, which existed from the 3rd century BC to the 7th century AD and is considered one of the three kingdoms of Korea.

The tomb was constructed in 357 AD as the burial site for King Tongmyong, the founder of the Koguryo Kingdom. It is a circular structure with a diameter of 46 meters and a height of 22 meters. The tomb was built using large stones and earth, and its design is similar to other tombs from the same period found in China.

The tomb complex is surrounded by a moat and a wall that are both 4 meters high. The entrance to the tomb is through a long tunnel that leads to a burial chamber in the center of the structure. The chamber is 7 meters in diameter and contains a stone coffin that is believed to hold the remains of King Tongmyong.

The tomb has been excavated several times over the years, and many valuable artifacts have been found inside, including gold and silver ornaments, weapons, and pottery. These artifacts are now on display in the Koguryo Tombs Museum, which is located near the tomb complex.

The Tomb of the Koguryo Kingdom is an important historical site in North Korea and is considered a national treasure. It was declared a UNESCO World Heritage site in 2004 as part of the "Complex of Koguryo Tombs" listing.