Multiracial children are the largest demographic group in the United States among individuals under the age of 18 (Pew Research Center, 2015), but their developmental processes are understudied. Parents and caregivers play an important role in preparing youth to navigate racialized society by teaching them to understand what it means to be a member of a racial-ethnic group (Hughes et al., 2006). However, this process is more complex in multiracial families, where youth belong to multiple racial-ethnic groups. Thus, the purpose of the present study was to develop and validate the first measure of racial-ethnic socialization for Multiracial youth, the Multiracial Youth Socialization (MY-Soc) Scale, to assess the unique messages that are communicated in multiracial families regarding topics of race, ethnicity, and culture. Using a sample of 901 Multiracial emerging adults (m age = 22.43), we separately captured the socialization practices of two of the youths' primary caregivers from the youths' perspective. Exploratory and confirmatory factor analyses supported a 62-item scale measuring eight types of socialization: