Harith ibn Abi Shamir Al-Gassani (Arabic: اَلْحَارِث ٱبْن أَبِي شَمِر الغَسَّانِي|al-Ḥārith-bn-Abī-Shamir al-Ghassānī) was the Ghassanid Arab Christian governor of Sham (Levant or Greater Syria) which was in the domain of the Byzantine Empire. He was a contemporary of Muhammad and King of Damascus now in modern-day Syria. He received a letter from Muhammad in which he was invited to Islam. Harith was a member of the Ghassanid dynasty, which ruled parts of Sham.
After the Hudaybiyah Treaty, Muhammad sent a letter to Harith Gassani which read as follows: