The Siloam inscription or Shiloah inscription (Hebrew: כתובת השילוח, or Silwan inscription,) known as KAI 189, is a Hebrew inscription found in the Siloam tunnel which brings water from the Gihon Spring to the Pool of Siloam, located in the City of David in East Jerusalem neighborhood of Shiloah or Silwan. The inscription records the construction of the tunnel, which has been dated to the 8th century BC on the basis of the writing style. It is the only known ancient inscription from ancient Israel and Judah which commemorates a public construction work, despite such inscriptions being commonplace in Egyptian and Mesopotamian archaeology.

It is among the oldest extant records of its kind written in Hebrew using the Paleo-Hebrew alphabet, a regional variant of the Phoenician alphabet. The inscription is held by the Istanbul Archaeology Museum.

Turkey has denied Israel's requests to be sent the inscription, on the basis that it was found in what is today East Jerusalem, which is considered occupied Palestinian territory under international law by the vast majority of the international community, though Israel disputes this.