ABSTRACT That individuals attain socioeconomic status (SES) through their own effort and ability, which is a staple pillar of the meritocratic ethos and has been a popular topic of inquiry within social psychology. However, this focus on merit overshadowed other important causal factors that contribute to one’s SES, such as opportunity and chance. This study presents psychometrically validated scales measuring one’s causal beliefs of SES attainment for themselves (agency beliefs) and others (society beliefs). Utilizing a nationally representative sample, participants completed 68 items of causal agency and society beliefs for low and high SES attainment. Through factor analyses, item response theory, and careful item reduction, three subscales and six dimensions measuring (1) merit (effort and ability), (2) opportunity (social connections and privilege), and (3) chance (luck and fate) are introduced for each belief system. Correlation analyses reveal general support for construct validity. Implications and future directions are discussed.