Xaisomboun (also Saysomboun, ) was a special zone (khetphiset) of Laos, located in the north of the country, near the capital Vientiane. The special zone was created 1994 with area split off from the provinces Vientiane, and Xiangkhoang. It was dissolved on January 13, 2006.

On September 23, 2004 the districts Hom and Longsane were merged. The new district, still named Hom, was reassigned to Vientiane Province. On June 27, 2005 the districts Phun and Xaysomboun were merged, with the new district still named Xaysomboun.
On January 13, 2006 the special area was dissolved. Xaysomboun district was reassigned to Vientiane Province, while Thaton went to Xiangkhoang Province.