An extensive body of research has documented the relation between social class, as indexed by socioeconomic status (SES) and subjective social status (SSS), and a host of outcomes, including physical and mental health, academic achievement, and educational attainment. Yet, there remains ambiguity regarding how best to conceptualize and measure social class. This article clarifies definitional and measurement issues related to the assessment of SES and SSS, addresses their importance and relevance for psychological research, and reviews best practices with regard to measurement and assessment. We conclude by discussing the integration of social class with other markers of social position to promote the advancement of psychological science.