Purpose The purpose of this case study is to assess and compare the performance of an academic library, in the United Arab Emirates (UAE), before and during the coronavirus disease 2019 (COVID-19) pandemic. Design/methodology/approach The study is based on data collected from the library management system, usage reports of online databases, and monthly reports and archives to evaluate and assess library performance in managerial activities, collection development, collection treatment, collection circulation, usage of digital resources, quality control, reference services and information literacy activities. Frequency distributions and non-parametric tests were used in identifying differences and testing hypotheses. Findings The study found that library performance before the COVID-19 pandemic outperformed library performance during the pandemic in collection development, collection treatment, collection circulation, access and use of digital resources, quality control and information literacy. On the other hand, the library demonstrated higher performance in managerial activities and reference services during the COVID-19 pandemic than that of before the pandemic period. Interestingly, the analysis of the Wilcoxon signed-ranks test revealed statistically no significant difference in the library performance before and during the COVID-19 pandemic. The results supported all the eight hypotheses stated in this study. Research limitations/implications This is a case study based on data collected from an academic library in the UAE before and during the COVID-19 pandemic. The findings may not be generalized and may differ if more data are analyzed from many academic libraries. Practical implications COVID-19 pandemic is a turning point for library managers to increase the number of digital resources and services, to ensure that library staff are equipped with essential and up-to-date information and communication technology (ICT) skills and knowledge, to ensure that library users are equipped with essential and up-to-date information literacy skills and knowledge. These will enable them to satisfy users' information needs and ensure library operation in disasters and crisis periods. Originality/value This is one of the few studies conducted in the Gulf Cooperation Council (GCC) countries to evaluate library performance before and during COVID-19 pandemic. The findings of the study could be an important reference in understanding how libraries responded to COVID-19 pandemic in the Middle East. The results of the study may contribute to the provision of digital resources and services during the pandemic and disasters in the UAE and the Arab world.