Mask usage is an effective measure to prevent severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection; however, mask reuse is not recommended. Studies examining the factors associated with mask reuse during the coronavirus disease (COVID-19) pandemic are limited. This nationwide survey aimed to determine the prevalence and factors associated with mask reuse among Taiwanese citizens during the pandemic. From 18 May through 31 May 2020, a computer-assisted telephone interview system was used to randomly select Taiwanese citizens for interview regarding COVID-19-preventive behaviors and knowledge on mask usage. For a total of 1075 participants, the overall mean age was 57.4 years, and 82.2% of participants reported mask reuse during the COVID-19 pandemic. After controlling for other covariates, participants who had a greater knowledge of mask usage or had a high supply of masks were less likely to reuse masks during the pandemic. Moreover, generalized estimating equations (GEE) analysis showed that, compared with the participants' mask-wearing behaviors before the COVID-19 pandemic, they were more likely to reuse masks during the pandemic. Thus, it is imperative to educate people on the correct usage of masks. Furthermore, the government should provide sufficient masks to the general population to reduce mask reuse.