There is increasing recognition of the need for culturally sensitive services for individuals who identify as transgender and gender nonconforming (TGNC), and only recently have empirical studies appeared in the literature that inform best practices for TGNC people. Competent, culturally appropriate clinical services and research depend upon methodologically sound assessment of key constructs, but it is unclear whether appropriate self-report or clinician-rated assessment tools for adults exist. This article reviewed existing published measures to identify areas of strength as well as existing gaps in the available research. The search strategy for this systematic review identified any published article describing a self-report or clinician-rated scale for assessing transgender-related concerns. Each measure was reviewed for information on its scope, reliability, validity, strengths, limitations, and source. The majority of these questionnaires was developed with the TGNC communities and targeted important factors that affect quality of life for TGNC people. Limitations included limited evidence for validity, reliability, and sensitivity to change. Overall, the field is moving in the direction of TGNC-affirming assessment, and promising measures have been created to monitor important aspects of quality of life for TGNC people. Future research should continue to validate these measures for use in assessing clinical outcomes and the monitoring of treatment progress.