The Chaldean Catholic Church (Classical Syriac: ܥܕܬܐ ܟܠܕܝܬܐ ܩܬܘܠܝܩܝܬܐ, ʿĒdtā Kalḏāytā Qāṯōlīqāytā; الكنيسة الكلدانية, al-Kanīsa al-Kaldāniyya; Latin: Ecclesia Chaldaeorum Catholica) is an Eastern Catholic particular church (sui iuris) in full communion with the Holy See and the worldwide Catholic Church. It uses the East Syriac Rite in the Syriac language and forms part of the Syriac tradition.
The church is headed by the patriarch of Babylon of the Chaldeans, currently Louis Raphaël I Sako, and is based in the Cathedral of Our Lady of Sorrows in Baghdad, Iraq. As of 2018, it counted approximately 616,639 members globally, with most residing in Iraq and significant diasporic communities in North America, Europe, and Australia.