The worldwide growth in learners of sign languages as second or additional languages (L2/Ln), some of whom become sign language teachers and interpreters, necessitate an assurance that the learners have the knowledge and skills in sign languages, which is attained through assessment. Sign language assessments are crucial. Without assessments, teachers and interpreters could have been developed with less than optimal skills. A consequence would be language and communication gaps for the learners. Different L2/Ln sign language assessments are described in terms of its purposes, target populations, formats, domain areas, and psychometrics. International, national, and provincial bodies of certifying organizations vary widely in the requirements and assessments they provide, including test forms, content, administration, and scoring criteria. The variations create confusion as to test measures, and it is imperative that assessment developers standardize language skills and knowledge of sign language learners and language domains in the tests as they develop.