yā sīn (also Yaseen; Arabic: يس‎) is the 36th chapter (surah) of the Quran. It has 83 verses (ayahs) and is one of the Meccan surahs, although some scholars maintain that verse 12 is from the Medinan period.[1]

It is named "yā sīn" because the chapter starts with the "disconnected" or "mysterious" (Muqatta'at) Arabic letters: يس (yā sīn). That the name of the chapter comes from the two letters of the first verse of the chapter,[2] which has caused much scholarly debate, and which Tafsir al-Jalalayn, a Sunni exegesis (tafsir), interprets by saying, "God knows best what He means by these [letters]."[3]

The surah focuses on establishing the Qur'an as a divine source, and it warns of the fate of those who mock God's revelations and are stubborn. The surah tells of the punishments that plagued past generations of nonbelievers as a warning to present and future generations. Additionally, the surah reiterates God's sovereignty as exemplified by His creations through signs from nature.

The surah ends with arguments in favor of the existence of Resurrection and God's sovereign power.