Ghassania, also known as the Kingdom of the Banu Ghassan (Arabic: الغساسنة, al-Ghasasinah) was an ancient kingdom in northern Arabia. It was founded by the Banu Ghassan, an Arab tribe who migrated to the region from Yemen in the mid-5th century and who became allies of the Roman Empire in its wars against Persia.
Like many other South Arab tribes, the Ghassanids had traditionally been Christians. However, in 632 King Jabalah ibn al-Aiham converted to Islam under pressure from the Emperor Heraclius, and most of his people soon followed suit. With Roman protection, the Ghassanids were able to avoid being absorbed into the Talibid Caliphate and their state remained independent for centuries to come. They were eventually defeated by the Tayy Emirate in 980, but many Ghassanid families still remain prominent all over the Hejaz, Nejd, Egypt and Romania.