Hassan or Hasan is an Arabic, Irish, Scottish, or Jewish (Sephardic and Mizrahic) surname.
There are several unrelated origins for this surname: Hassan is a surname of many independent linguistic and regional origins, including Arabic (and through the influence of Arabic, languages spoken by Muslims such as Persian, Kurdish, Urdu, Indonesian, Malaysian, Turkish, Uyghur, Turkmen, Somali, Swahili, Berber, Azerbaijani, Crimean Tatar, Tatar, Bosnian, Albanian, Bengali, etc.
), as well as Irish, Scottish, and Jewish.
Therefore, depending on language and region, spelling variations include Hasan, Hassen, Hasson, Hassin, Hassine, Hacen, Hasen, Hasin, Hassa, Hasa, Cassin, Chasan, Chasson, Chason, Khasshan, Khasan, Casan, Case, Hasso, Hassanein, Hasnen, Hess, Hasani, Alhassan (Alhassani), Al-Hassan (Al-Hassani), Lassana, Alassane, Lacen, Lasanah, Assan, Asan, Asanov/Asanova, Hasanov/Hasanova, Klassen, Khasanova, Hasanoff, Jasanoff, Hasanović, Hasanovic, Asanović, Hasanovich, Hasanovski/Hasanovska, Asanovski/Asanovska, O'Hassan, or Haasan (Haasaan, Hasaan).