As schools adapt curriculum and learning environments to better prepare students for entry into an increasingly globalized society, cultivating intercultural competencies in K-12 in-service educators is of heightened importance. The purpose of this study was to develop and validate a new instrument designed to assess these competencies called the Intercultural Competency Measure for Educators (ICME). Byram (1997) defines intercultural competencies as the ability to effectively communicate, understand, and work with people from diverse cultural backgrounds. Deardorff (2006) adds to this a call for action, which lends itself to the critical cosmopolitanism framework that guides this study. A pilot study was used to develop a four-factor theoretical intercultural competencies framework through a process defined in this study. Reliability and validity were examined using data collected from K-12 in-service educators at schools in the United States and Canada. An Exploratory Factor Analysis suggested a revision of the constructs to include five factors: Curriculum, Diverse Student Inclusion, Cross-Cultural Openness, Collaboration and Adaptation, and Systematic Awareness. Construct validity was tested using Confirmatory Factor Analysis and supported by examining demographic data using parametric tests. The emergence of a factor related to systematic awareness highlights teachers' increased role in addressing the root causes of inequity in schools. The five-factor model provides a framework for schools wishing to further develop and assess intercultural competencies growth in teachers. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]