Given the paucity of research on mobile-assisted language learning (MALL) in secondary schools in China, this retrospective case study explored the psychological processes underlying the non-voluntary MALL experiences of Chinese secondary school students during a lockdown to contain the spread of COVID-19. Drawing on prior technology acceptance studies, we proposed a research model comprising nine latent constructs, and tested it with data collected through a questionnaire survey (N = 265). The results of a structural modeling test showed that subjective norms and attitudes toward MALL were significant predictors of the behavioral intention to use it, whereas perceived usefulness and perceived ease of use mediated other factors that influence attitudes. The findings support the use of the technology acceptance model in investigating MALL acceptance. Implications for the better implementation of MALL, especially in the context of secondary schools in China are also discussed.