As globalization expands, individuals working or studying abroad often face the challenge of adapting to unfamiliar cultural settings. Prolonged exposure to these environments can lead to heightened stress and, in some cases, burnout. This chapter examines the relationship between expatriate stress and cultural intelligence (CQ), showcasing CQ as a critical tool for mitigating stress and fostering well-being in cross-cultural contexts. Surveying over 300 expatriates from 40 countries who engaged in international work or study for at least three months, this study applied validated measures to assess CQ levels and stress. Statistical analyses revealed a strong negative correlation between CQ and stress, demonstrating that individuals with higher CQ experience significantly reduced stress levels in international environments. Notably, variables such as age, motivation, and time spent abroad had no statistically significant impact on stress levels, emphasizing CQ as the decisive factor. The findings highlight the importance of enhancing CQ through intercultural training programs, enabling individuals to navigate cultural differences more effectively and maintain mental resilience. Recommendations for HR professionals and leaders include developing targeted interventions to boost CQ, ensuring expatriates are equipped for success in multicultural settings. This chapter reinforces the value of CQ as a cornerstone for well-being, productivity, and effective collaboration in today’s diverse and interconnected global workforce.