Despite the current need for reliable and valid test instruments in different countries in order to monitor the sign language acquisition of deaf children, very few tests are commercially available that offer strong evidence for their psychometric properties. This mirrors the current state of affairs for many sign languages, where very little research is available. No previous empirical study has focused explicitly on the linguistic, methodological, and theoretical issues involved in the process of adapting a test from a source sign language to a target sign language. Problems during the adaptation process can arise from linguistic differences between the source and the target language and differences in the source and the target cultures. Both are important aspects that need to be considered in the adaptation of a sign language test from a source to a target language. This study proposes a model for sign language test adaptation, based on the adaptation of the British Sign Language Receptive Skills Test to German Sign Language. The model includes different methodological steps, with a particular focus on construct validation. (Contains 4 notes, 4 tables, and 4 figures.)