In the holy book of Islam, the Quran, a Surah (سورة) is a chapter. The Quran contains 114 such chapters, widely different in length, ranging from the shortest, Al-Kawthar (merely three verses), to the longest, Al-Baqarah (286 verses).

Most Surahs usually deal with one specific topic or a cluster of related topics. These themes may vary from accounts of prophets and ancient nations to theological doctored, moral teachings, and laws that regulate aspects of life. The Surahs are not presented in chronological order of the revelation but are mostly categorized according to the length, where longer Surahs tend to come earlier in the Quran and shorter ones towards the latter part. Every Surah, with the exception of At-Tawbah, starts with the words "Bismillah ir-Rahman ir-Rahim" (In the name of Allah, the Most Gracious, the Most Merciful), which is an invocation and a dividing line between the chapters. A knowledge of the individual Surahs and the context is very important to the better understanding of the message of the Quran.