This article is concerned with developing an instrument to assess Culturally Responsive Teaching. A study was conducted to explore the process of developing a valid and reliable CRT Assessment Instrument. Teaching behaviors widely accepted to indicate culturally responsive teaching were operationalized and an observation instrument was developed to assess teachers' use of culturally responsive teaching in applied classroom settings. Teachers were observed using the instrument and it was evaluated for its reliability and validity. Results of the study indicated that the instrument was found to have acceptable inter-rater reliability for approximately half of the indicators. The results supported the content validity of the instrument but construct validity was lacking. Through this research, it was discovered that indicators for Culturally Responsive Teaching observation must be descriptive and physically based to obtain reliable and quantitative data.