The spring wire clip fastens fence wire to T-posts. The clip is constructed from hardened high carbon spring steel and has a geometry that allows the clip to be installed with no tools. The middle of the clip has a shape complementary to the T-post spine, typically a “V” shape, such that the clip wraps around the spine and the two ends extend laterally. Each end has a curl that can engage the fence wire on either side of the T-post. The clips can be installed five times faster than with standard twist-type clips and can be repositioned, or reused, as the attachment is not permanent.