Sociological research on mental health focuses on a multitude of dynamic processes, including changes in psychological symptoms or the onset of a mental disorder, the course and outcome of mental health problems, and the associations of mental health with a wide variety of time-varying social risk and protective factors. I argue that scholars studying mental health have, thus far, only scratched the surface of the temporal dynamics upon which mental health and illness rest. Two broad research issues are reviewed to illustrate important temporal issues that have been neglected or understudied in mental health research: (1) specific dimensions of temporality, which focus on dynamic processes at the individual level, and (2) the age-period-cohort model, which focuses on mental health at the population level. Priority topics for future research that takes time seriously are recommended.