The aim of this review was to describe how the coronavirus disease 2019 (COVID-19) lockdown affected the self-care behaviors of people living with type 2 diabetes. A systematic rapid review was conducted using four electronic databases. Studies reporting on the lockdown's impact on at least one of the self-care behaviors that were published from January 2020 through October 2021 were included. Findings were synthesized narratively, using the Association of Diabetes Care & Education Specialists ADCES7 Self-Care Behaviors as a framework. The methodological level of evidence and quality ratings of the articles were assessed using the Joanna Briggs Institute Appraisal Checklist. Fifteen articles were included. Most studies reported on at least five of the self-care behaviors. There were reported increases in diabetes-related stress, as well as in increases in dietary intake and changes in the timing of meals. Physical activity was reported to decrease. Overall, taking medications and glycemic self-monitoring of blood glucose (SMBG) were unaffected by the lockdown. Of the studies reporting glycemic outcomes, the lockdown appeared to have little negative effect. None of the articles assessed all the self-care behaviors. The self-care behavior of SMBG was the least assessed. Most articles had a medium level of evidence and a medium to high quality rating (scores >60%). The findings from this review found the COVID-19 lockdown had a variable impact on diabetes self-care behaviors. Because the potential for future COVID-19 surges and/or other virulent transmissible diseases remains a concern, health care providers should continue to address the importance of self-care behaviors to mitigate the risk of poor health outcomes in people with diabetes.