Gumarcaj, sometimes rendered as Cumarcaj or Kumarcaaj, is an archeological site in El Quiché department of Guatemala. Gumarcaj is also known as Utatlán, the Nahuatl language name for the city. The name Gumarcaj is Quiché for "Place of old reeds".

Gumarcaj was the capital city of the Quiché Maya people in late Pre-Columbian times. The ruins of the city are a short distance from the modern city of Santa Cruz del Quiché.

The site was founded around 1400 for its defensive position, as it was a time of warfare in the Guatemala highlands. The city is situated on a hilltop surrounded by ravines.

The Spanish Conquistadores conquered the city in 1524.

Tecún Umán, the last Quiché king, was already dead; he was killed in battle with Conquistador Pedro de Alvarado in Quetzaltenango.

On Alvarado's orders, the city, together with the ruling nobles, were burned.

Cut stone originally facing the buildings was taken to build the new buildings of Santa Cruz del Quiché; the ruins were still being mined for construction material through the late 19th century, doing extensive damage to the remains of the old buildings.

The site was extensively documented in the colonial era. Miguel Rivera y Maestre wrote a report of the site for the government of Guatemala in 1834. In 1840 it was visited by travel writer John Lloyd Stephens. A more detailed plan of the site was made by Alfred P. Maudslay in 1887. Archeological excavations were made in the 1950s and the 1970s.

The site can be visited, although little restoration work has been done to it. Various temple pyramids, the remains of palaces (mostly reduced to mounds of rubble) and a court for playing the Mesoamerican ballgame can be seen.

Some modern Quiché, although officially Christian, still burn candles and incense at the ruined temples.