Tools for assessing object relations (ORs) are fundamental for psychodynamic theory, research, and practice. ORs play an important role in diagnostic and therapeutic processes, helping therapists to better understand and manage complex relational functioning in their patients. The clinical relevance of OR is also recognized by the first criterion of the Diagnostic and Statistical Manual of Mental Disorders, fifth edition Alternative Model for Personality Disorders. Our goal is to provide clinicians and researchers with an updated review of the available empirical tools to assess OR. We conducted a systematic search on APA PsycInfo and Pubmed and retrieved 42 instruments from the existing literature. Some of these assessment tools are well established in the scientific community. Among the less popular ones, we identified some instruments that show good potential and may be granted a further round of validation. We encourage the development of existing and new instruments within the framework of Kernberg's theory of personality organization, and a further inquiry into qualitative aspects of ORs dyads, which may help therapists obtain more sophisticated information on their patients' relational functioning.