This publication aims to provide a list of the main available test sites and laboratories where Ground-Penetrating Radar (GPR) equipment, methodology and procedures can be tested. It also ecompasses recommendations for the design of new GPR test sites. The catalogue is an outcome of the COST Action TU1208 "Civil engineering applications of Ground Penetrating Radar." Most test sites presented in this volume are located in Europe; information about a few extra-European facilities is included, as well. The catalogue will contribute to identifying new collaboration possibilities among European research teams and stimulate a stronger cooperation between academia and industry. Furthermore, the catalogue clarifies which are the existing and missing testing facilities in the various European regions, thus highlighting and possibly addressing current and near-future research needs. Scientists, GPR end-users and manufacturers can exploit the facilities listed in this catalogue to test and calibrate their equipment and inspection procedures, to investigate the feasibility of new applications, to plan and offer training activities, to verify and increase the level of their own experience with respect to specific applications, and more. Moreover, this publication represents a helpful reference for the preparation of new project proposals, as well as for the definition of the workplan of research initiatives and industrial ventures. It is worth stressing that test sites are central to any future Quality Assurance/Control strategy to be developed in the GPR field. Additionally, test sites are the only practical means of collecting experimental datasets in controlled conditions, to be analyzed and compared for the purposes of deriving knowledge about the performance of different GPR systems, antennas, procedures and algotithms. The list of facilities provided in this publication is not exhaustive. We hope that, in the future, this catalogue will progressively become more complete and we plan to update it on a regular basis; in particular, we are looking forward to enriching the list of facilities available outside Europe. The second edition of the catalogue is foreseen for Spring 2019 and will be presented during the 10th edition of the International Workshop on Advanced Ground Penetrating Radar (IWAGPR 2019, Rome, Italy, 3-5 July 2019). Scientists and professionals willing to contribute to the upcoming edition of this publication are welcome to take contact with us at tu1208@gpradar.eu.