The Perceived Stress Scale (PSS) is a popular instrument for measuring the degree to which individuals appraise situations in their lives as excessively uncontrollable and overloaded. Despite its widespread use (e.g., for evaluating intervention effects in stress management studies), there is still no agreement on its factor structure. Hence, the aim of the present study was to examine the dimensionality, measurement invariance (i.e., across gender, samples, and time), reliability, and validity of the PSS. Data from 11,939 German adults (73% women) were used to establish an exploratory bifactor model for the PSS with one general and two specific factors and to cross-validate this model in a confirmatory bifactor model. The model displayed strong measurement invariance across gender and was replicated in Study 2 in data derived from six randomized controlled trials investigating a web-based stress management training. In Study 2 (overall N = 1,862), we found strong temporal invariance. Also, our analyses of concurrent and predictive validity showed associations with depressive symptoms, anxiety, and insomnia severity for the three latent PSS factors. These results show the implications of the bifactor structure of the PSS that might be of consequence in empirical research.