Graphical tools to organise and represent knowledge are useful in terminology work to facilitate building concept systems. Creating and maintaining hierarchically structured concept relation maps while manually gathering data for terminological databases helps to gain and maintain an overview of concept relations, supports terminology work in groups, and helps new team members catching up on the subject field. This article describes our approach to support the building of concept systems in comparative legal terminology using the concept mapping software CmapTools (IHMC): we build hierarchically structured concept relation maps where linking lines with arrowheads between concepts of the same legal system represent generic-specific relations, and combined concept relation maps where dashed lines without arrowheads connect similar concepts in different legal systems.