The racial/ethnic disparities and average declines in science, technology, engineering, and mathematics (STEM) motivation during adolescence are worrisome. Although STEM motivational beliefs are theorized to function in conjunction with one another, the unique patterns and how they change over time for different racial/ethnic groups remain understudied. Using data from the High School Longitudinal Study (N = 18,260), we identified four and five patterns of math and science motivational beliefs in 9th and 11th grade, respectively, and examined their prevalence among Asian, Black, Latina/o, White, and Multiracial adolescents. We found patterns with overall high/low beliefs, patterns with varying levels of motivational beliefs, and patterns characterized by domain differentiation. Then, we charted the stability and changes in those patterns from 9th to 11th grade for each racial/ethnic group and how the patterns at 11th grade were associated with adolescents' STEM career expectations and high school math and science grade point averages.