The influence of the COVID-19 pandemic on mental health is of mounting concern to population-health researchers. While early reports indicated increases in mental health problems, noticeably absent from these studies is how mental health has changed in 2020 compared to previous years (2013-2019) and whether such trends vary by race/ethnicity. The present study used repeated cross-sectional data from the California Health Interview Survey (n ​= ​168,216) to systematically document trends in psychological distress scores (Kessler-6 scale; K6) and severe psychological distress scores (K6; 13+) from 2013 to 2020 and by race/ethnicity over the same period. Among all Californians we find that the reported average psychological distress scores increased by 22% between 2013 and 2020. Reported severe psychological distress scores increased 61% from 2013 to 2020. These increases were largely concentrated in the years 2017-2020. Increases in psychological distress were also especially pronounced among non-Latino/a White Californians (29% increase in K6 from 2013 to 2020), Latino/a Californians (14% increase in K6 from 2013 to 2020), and Asian Californians (35% increase in K6 from 2013 to 2020). Multiple and logistic regression models that accounted for sociodemographic and behavioral health covariates echoed these findings. Future research should continue to investigate secular trends in mental health that coincided with the COVID-19 pandemic and carefully situate the shifts into broader temporal perspective.