The pandemic of the Coronavirus 19 disease (COVID-19) has had significant impact on healthcare systems worldwide. The present study aims to investigate the service providers’ quality dimensions in public sector hospitals in the Republic of Serbia during the COVID-19 pandemic and to propose a sustainable model for healthcare improvement. The study was conducted from September 2021 to December 2021. A modified SERPERF quality measurement questionnaire was distributed to healthcare workers in nine secondary care public hospitals of the Serbian Autonomous Province of Vojvodina (APV). Six hundred one questionnaires were found to be complete in all aspects and compared to 528 questionnaires from the database of the Provincial Secretariat for Health Care obtained from healthcare workers before the COVID-19 outbreak. The present study suggests that supportive measures during the COVID-19 pandemic are effective and, from the providers’ perception, increase healthcare quality. Continual investment in healthcare would provide sustainable development of healthcare quality in the future, regardless of the pandemic conditions.