The Nea Ekklēsia (Greek: New Church) was a church built by Byzantine Emperor Basil I the Macedonian in Constantinople between the years 876–80. It was the first monumental church built in the Byzantine capital after the Hagia Sophia in the 6th century, and marks the beginning of middle period of Byzantine architecture. It continued in use until the Palaiologan period. Used as a gunpowder magazine by the Ottomans, the building was destroyed in 1490 after being struck by lightning.

Gold solidus of Emperor Basil I, with his son Constantine and Empress Eudokia Ingerina.Emperor Basil I was the founder of the Macedonian dynasty, the most successful in Byzantine history. Basil regarded himself as a restorer of the empire, a new Justinian, and initiated a great building program in Constantinople in emulation his great predecessor. The Nea was to be Basil’s Hagia Sophia, with its very name, "New Church", implying the beginning of a new era.

The church was built under the personal supervision of Basil, in the southeastern corner of the Great Palace complex, near the location of the earlier tzykanistērion (polo field). Basil built another church nearby, the "Theotokos of the Pharos". The Nea was consecrated on 1 May 880 by Patriarch Photius, and dedicated to Jesus Christ, the archangel Michael (in later sources, Gabriel), the Prophet Elijah (one of Basil’s favorite saints), the Virgin Mary and St Nicholas.