Background and Objective: The public health workforce has been overwhelmed in meeting COVID-19 demands while attempting to deliver core public health programs at a reduced capacity. There is limited understanding of the pandemic’s impact on the mental health of the public health workforce. This study will explore the extent of the pandemics impact on the mental health of Canadian public health workers and their intention-to-leave the workforce. Methods: In this cross-sectional study, participants are eligible to participate if they are public health professionals with advanced public health or discipline-specific education/training (e.g., nurses, epidemiologists) or other workers (e.g., family home visitors) and are employed in local public health units in Canada prior to March 2020 and for ≥8 months during the COVID-19 pandemic. Online communication channels (e.g., social media, email) of national and provincial public health organizations are being used to recruit participants. Data are being collected via an online survey on socio-demographic and workplace factors, burnout, anxiety, depression, and intention-to-leave. Descriptive statistics will be reported on the state of mental health and intention-to-leave. To determine who is at greatest risk, we will compare outcomes by socio-demographic (e.g., gender, ethnicity) and workplace factors (e.g., supervisor support) using regression analyses. Results: Recruitment and data collection began mid-November 2022 and will be completed by January 2023. To date, 310 surveys have been completed, with the sample consisting of frontline public health/community providers (57%), program/project management staff (20%), senior management (5%), program assistants (5%), Chief Medical Officers of Health/Medical Officers of Health (1%), and other roles (12%). Final data analysis will be completed by February 2023. Conclusions: Understanding the extent to which the mental health of the public health workforce has been impacted by the COVID-19 pandemic can inform strategic workforce planning, improve recruitment and retention efforts, and promote positive psychological health of workers.