Abstract: With globalization, corporations increasingly have to consider both domestic stakeholders and overseas stakeholders (i.e., international publics) in their corporate social responsibility (CSR) practice. Digitalization empowers international publics to scrutinize and react to a (multinational) corporation’s CSR strategy, further affecting corporate outcomes of CSR practice. Drawing on the social media context and attribution theory, this study investigated international publics’ reactions to corporate disaster relief, an emerging type of mobile-enhanced CSR (i.e., mCSR) practice, in the U.S. and China by looking at individuals’ engagement with mobile social media during disasters, attribution of CSR motives, and level of CSR skepticism. Using structural equation modeling (SEM) analysis, the survey data of randomly recruited Americans (n = 816) and mainland Chinese (n = 430) suggested that mobile social media engagement reinforces the values-, strategic-, and stakeholder-driven motives of mCSR in the U.S. and China. Egoistic-driven CSR motives elicited publics’ skepticism toward mCSR, while values- and stakeholder-driven motives inhibited skepticism in both countries. However, the effect of strategic-driven motives on skepticism was inconsistent internationally. Lastly, CSR skepticism triggered negative relational outcomes between the mCSR-performing corporation and various stakeholders in both countries. This study advances CSR and attribution theory and contributes to the practice of CSR, public relations and international business in the social media and disaster response context.