Introduction: A psychologically safe work environment plays a crucial role in shaping employees' wellbeing. Studies have consistently linked supportive and authentic workplace cultures to improved mental and physical health outcomes. In contrast, when organisations promote a culture of relentless forced positivity - referred to as toxic positivity - it can have adverse effects on employees' mental health. Despite its growing recognition, toxic positivity remains underexplored in workplace research. Purpose: This study investigated whether shame and emotional exhaustion, in serial, would mediate the relationship between toxic positivity in the workplace and the tendency toward job withdrawal behaviours. Method: A sample of 301 Australian employees (Mage = 34.2, SD = 10.6; 76.4% female), recruited via university platforms and social media sites, completed an online, confidential, and anonymous survey. Results: The results indicated that higher levels of toxic positivity in the workplace were associated with increased experiences of shame, emotional exhaustion, and a greater likelihood of job withdrawal. Moreover, the results supported a serial mediation model in which shame and emotional exhaustion jointly explained the relationship between toxic positivity in the workplace and job withdrawal. Conclusions: These findings highlight the potential risks of promoting overly positive narratives in workplace culture, emphasising that such approaches may undermine employee wellbeing. Organisations are therefore encouraged to recognise the nuanced effects of positivity and avoid blanket applications of optimistic messaging. Further investigation is needed to deepen our understanding of how toxic positivity contributes to emotional strain and behavioural responses on an individual level.