Abu al-Hasan al-Ash'ari (Arabic: أَبُو ٱلْحَسَن ٱلْأَشْعَرِيّ, romanized: Abū al-Ḥasan al-Ashʿarī; 874–936 CE) was an Arab Muslim theologian known for being the eponymous founder of the Ash'ari school of kalam in Sunnism.
Al-Ash'ari was notable for taking an intermediary position between the two diametrically opposed schools of Islamic theology prevalent at the time: Atharism and Mu'tazilism. He primarily opposed the Mu'tazili theologians on God's eternal attributes and Quranic createdness. On the other hand, the Hanbalis and traditionists were opposed to the use of philosophy or speculative theology, and condemned any theological debate altogether.