There are many misconceptions about the use of self-rated scales in research and clinical practice. Self-rated scales are a unique and valuable tool in mental health settings because the information is reported directly by the patient. They can be a practical tool within a variety of settings, including mental health research, screening, assessment and treatment. This paper draws upon widely used self-rated scales such as BASIS-24, SF-36, PSC, and Prepare-Enrich, to illustrate potential benefits of use. Additional information regarding selected scales such as target audience, subscales, countries and languages validated for use are provided as well. Four types of measurement invariance are also described to provide explanation on how reliability and validity are established. It is essential to test the measurement invariance of self-rated scales across various ethnic groups, cultures, and languages to assure that the tools measure the same constructs cross-culturally. Implications for use as well as application of these scales and research are discussed.