One of the most impressive structures in Jerusalem’s ancient landscape is the tower that was built to surround and protect the Gihon Spring, Jerusalem’s perennial water source. The structure, first discovered by Reich and Shukron (2004), encompasses the cave in which the spring sprouts from, with walls 7 m thick built of large boulders. The Spring Tower, along with the other features relating to it, were all attributed to the Middle Bronze Age II, based on their architectural and stratigraphical relationship, the type of architecture, and the pottery found. In the continued excavations carried out by the Israel Antiquities Authority along the outer, eastern face of the Spring Tower, it was noted that at least the northeast side of the tower was not built on bedrock, but rather on layers of sediment, which were sealed by the massive boulders at the base of the tower. In order to provide an absolute dating for the structure, two sections were sampled for radiocarbon (14C) dating beneath the foundation stones at two locations. Scenarios for the construction of the tower during Middle Bronze Age (MB) and Iron Age II are considered, based on the new 14C data, yielding a series of dates, the latest of which falls in the terminal phases of the 9th century BCE, alongside previous excavation data.