BACKGROUND: Theories highlight the important role of chronic stress in remodeling HPA-axis responsivity under stress. The Perceived Stress Scale (PSS) is one of the most widely used measures of enduring stress perceptions, and no previous studies have evaluated whether greater perceptions of stress on the PSS are associated with cortisol hypo- or hyperactivity responses to the Trier Social Stress Test (TSST). OBJECTIVE: To examine if high perceived stress over the past month, as measured by the PSS, alters cortisol and subjective acute stress reactivity to the TSST in healthy young adults. METHODS: Five studies across three laboratories involving healthy young adults (N = 585) were conducted. Participants were exposed to the TSST, and cortisol levels and subjective stress responses were measured. Studies 1-2 served as exploratory, and Studies 3-5 as explanatory, with pre-registered hypotheses. RESULTS: Higher PSS scores were consistently associated with greater acute subjective stress perceptions during the TSST across four out of five studies. Meta-analytic results revealed that higher perceived stress on the PSS was associated with blunted cortisol reactivity to the TSST. This cortisol hyporeactivity effect was more pronounced in studies using a combined speech and arithmetic TSST protocol compared to a speech-only protocol. Depressive symptoms did not significantly alter cortisol reactivity effects in these studies. CONCLUSION: Persistent high perceived stress over the past month may be associated with greater acute stress perceptions and blunted cortisol reactivity to the TSST. These findings highlight the potential importance of persistent perceived stress in HPA-axis responses to acute stress in healthy young adults, with potential implications for understanding stress-related health risks. Further research is needed to explore the underlying mechanisms and extend findings to diverse populations.