Public health restrictions caused by the COVID-19 pandemic have dramatically impacted children and youth’s ability to engage in the recommended amount of physical activity (PA), sedentary behaviour (SB), and sleep (‘movement behaviours’) for optimal health. There is heightened concern of the impact of this sudden ‘time out’ of active play for our most vulnerable children and youth including those living with disabilities who have a higher prevalence of multiple chronic conditions and less access to PA. PURPOSE: To assess the acute and longer-term impact of COVID-19 restrictions on the movement behaviours and guideline adherence in Canadian children and youth with disabilities. METHODS: Parents of school-aged children and youth with disabilities completed an online survey to assess their child’s previous 7-day PA, SB, and sleep. Parents’ perceived changes in their child’s movement behaviours between pre-COVID-19 and (a) April-May 2020 (time 1; N = 151) and (b) April-November 2020 (time 2; N = 87) were also assessed. Descriptive statistics were used to analyze child behavioural patterns and guideline adherence. RESULTS: At time 1, 5.3%, 13.2%, and 66.2% of children and youth met the individual guidelines for PA, SB, and sleep, respectively. Only 1.3% of children and youth met all three movement guidelines. Similarly, at time 2, 7.2%, 20.7%, and 66.3% of children and youth met the individual guidelines for PA, SB and sleep, respectively; none met all three movement guidelines. Parents reported their child to spend less time in both outdoor (60% vs. 62.1%) and indoor (46% vs. 60.9%) PA, and more time in recreational screen time (83.5% vs. 77%) across time 1 and 2, respectively. The majority of parents reported their child’s sleep quantity and quality to be the same as pre-pandemic levels for both time 1 (53.1% and 57.3%) and time 2 (77.6% and 64.4%). CONCLUSIONS: These results show very concerning PA and SB profiles of children and youth with disabilities over the early and subsequent periods of the COVID-19 pandemic compared to pre-COVID-19. Immediate action at the programmatic and policy levels is need for more accessible and inclusive strategies to increase PA and reduce SB in this vulnerable population of children and youth. Supported by Canadian Tire Jumpstart Charities