The article presents the development and initial validation of the COVID Stress Scales (CSS), a set of measures designed to assess COVID-19-related stress and anxiety symptoms. The CSS was developed to better understand and assess COVID-19-related distress and was intentionally designed to be adaptable for future pandemics. The scales were validated in two large, population-representative samples from Canada and the United States. The study identified a stable 5-factor solution, corresponding to scales assessing COVID-related stress and anxiety symptoms: Danger and contamination fears, fears about economic consequences, xenophobia, compulsive checking and reassurance seeking, and traumatic stress symptoms. The scales performed well on various indices of reliability and validity, including internal consistency and convergent and discriminant validity. The intercorrelations among the scales provided evidence of a COVID Stress Syndrome. The CSS offers promise as a tool for understanding and identifying individuals in need of mental health services during and after the pandemic.The article presents the development and initial validation of the COVID Stress Scales (CSS), a set of measures designed to assess COVID-19-related stress and anxiety symptoms. The CSS was developed to better understand and assess COVID-19-related distress and was intentionally designed to be adaptable for future pandemics. The scales were validated in two large, population-representative samples from Canada and the United States. The study identified a stable 5-factor solution, corresponding to scales assessing COVID-related stress and anxiety symptoms: Danger and contamination fears, fears about economic consequences, xenophobia, compulsive checking and reassurance seeking, and traumatic stress symptoms. The scales performed well on various indices of reliability and validity, including internal consistency and convergent and discriminant validity. The intercorrelations among the scales provided evidence of a COVID Stress Syndrome. The CSS offers promise as a tool for understanding and identifying individuals in need of mental health services during and after the pandemic.