The Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.28 to 1.39 billion baptized Catholics worldwide as of 2024. It is among the world's oldest and largest international institutions, and has played a prominent role in the history and development of Western civilization. The church consists of 24 sui iuris churches, including the Latin Church and 23 Eastern Catholic Churches, which comprise almost 3,500 dioceses and eparchies located around the world. The pope, who is the bishop of Rome, is the chief pastor of the church. The Diocese of Rome, known as the Holy See, is the central governing authority of the church. The administrative body of the Holy See, the Roman Curia, has its principal offices in Vatican City, a small independent city-state and enclave within the Italian capital city of Rome, of which the pope is head of state.

कैथोलिक कलीसिया या रोमन कैथोलिक कलीसिया ईसाई धर्म में वैश्विक ईसाई कलीसिया की एक मुख्य शाखा, तथा सबसे बड़ी कलीसिया है, जिसके अनुयायी रोम के वैटिकन नगर के पोप को अपना धर्माध्यक्ष मानते हैं। ईसाई धर्म की दूसरी मुख्य शाखा प्रोटेस्टैंट कहलाती है और उसके अनुयायी पोप के धार्मिक नेतृत्व को नहीं स्वीकारते। कैथोलिकों और प्रोटेस्टैंटों की धार्मिक मान्यताओं में और भी बड़े अंतर हैं।