Coronavirus disease 2019 (COVID-19), an infectious disease pandemic, affected millions of people globally, resulting in high morbidity and mortality. Causing further concern, significant proportions of COVID-19 survivors suffer from the lingering health effects of severe acute respiratory syndrome virus 2 (SARS-CoV-2), the pathogen that causes COVID-19. One of the diseases manifesting as a post-acute sequela of COVID-19 is new-onset diabetes. This systematic review and meta-analysis will perform a comprehensive and systematic literature search to estimate the burden of new-onset diabetes after COVID-19. Specifically, this study will estimate the magnitude of the incidence, risk, and population-attributable fraction of new-onset diabetes. The study will also explore and summarize the data on the natural history or clinical course of the new-onset diabetes cases. Five bibliographic databases, including PubMed, MEDLINE, Embase, Scopus, and Web of Science, will be searched for eligible studies. The World Health Organization COVID-19 Research Database, preprint servers, and conference abstracts will also be searched. Cohort studies of COVID-19 patients of all ages providing data on new cases of diabetes in the post-acute phase of the illness will be included. The comparators to estimate the pooled risk ratio will be those with no diagnosis of COVID-19 or those infected with other respiratory tract infections. The findings of this study will likely inform clinical practice, public health guidelines, and policies for early detection and treatment of new-onset diabetes cases in the long-COVID phase. This protocol has been registered in the International Prospective Register of Systematic Reviews (PROSPERO: No.CRD42020200432).