哈里发国（阿拉伯语：خلافة‎，意为继承）是由最高宗教和政治领袖哈里发领导的伊斯兰国，穆斯林世界存在的穆斯林帝国通常被称为哈里发国。从概念上说，哈里发国是代表全部虔诚穆斯林（乌玛）的主权国家，根据伊斯兰教法由哈里发统治。

在其早期，第一个哈里发国正统哈里发，有着直接民主（shura）的成分，其首先由穆罕默德的直接追随者和家族领导，以延续他所创建的宗教体制。

哈里发国是“逊尼派的核心领导概念，这是在伊斯兰早期由穆斯林多数所创建的共识”。逊尼派规定，作为国家元首，哈里发应当由穆斯林或其代表选举产生。而什叶派则认为，哈里发应是伊玛目，由真主从默罕默德家族中拣选。自四大哈里发之后，直到1924年，哈里发国由不同的王朝统治，第一个是倭马亚王朝，接下来的几个王朝有时各自自命正统，最后的哈里发王朝为奥斯曼帝国。

A caliphate (Arabic:خِلافة‎ khilāfa) is an area containing an Islamic steward known as a caliph (Arabic:خَليفة‎ khalīfah  pronunciation )—a person considered a religious successor to the Islamic prophet, Muhammad (Muhammad ibn ʿAbdullāh), and a leader of the entire Muslim community. The Rashidun caliphs, who directly succeeded Muhammad as leaders of the Muslim community, were chosen through shura, a process of community consultation that some consider loosely to be an early form of Islamic democracy. During the history of Islam after the Rashidun period, many Muslim states, almost all of them hereditary monarchies, have claimed to be caliphates. Even though caliphs were thought to go back to Muhammad, they were not thought of as having the same prophetic power as he did.