Soil compaction adversely affects biological properties and functions of the soil leading to substantial crop productivity losses. Typically, soil compaction is measured using manual soil probes that provide single-point data resulting in hundreds of manual measurements needed to map an entire field. A ground penetrating radar (GPR) system measures the dielectric permittivity of the soil at a high frequency as it is pushed over the soil. This potentially offers an opportunity to develop detailed soil compaction maps even for large fields. We tested the ability of a ground-coupled antenna GPR to measure soil compaction. The GPR signal intensity was lower for compacted soil than for non-compacted soil when the GPR was in permanent contact with the soil during measurements.