Based upon the interdisciplinary literature on organizational flexibility, the study investigates positive and negative effects of perceived flexibility requirements (PFR) on worker well-being. The authors define PFR as perceived expectations conveyed by the organization to its employees, regarding self-directed behavior related to flexibility and efficiency in organizational practices; their content can refer to (1) task fulfillment, (2) career development, (3) learning, and (4) working time. Based on a heterogeneous sample of N = 931 employees, the authors tested a structural equation model, in which time pressure, work–family conflict, and personal initiative mediated between PFR and strain. Negative effects on well-being were most pronounced for PFR with regard to working time and mediated via time pressure and work–family conflict. PFR related to task fulfillment had both negative and positive effects via time pressure, but also stimulating employee initiative. The other two dimensions of PFR explained only small amounts of additional variance in dependent variables.