Following the increased implementation of mobile learning across the globe, specifically in the area of mobile-assisted language learning (MALL; Burston, 2015; Duman et al., 2015), the current paper provides an evaluation of the highly popular MALL application Duolingo. Specifically, this evaluation targets how effectively instructed second language acquisition (ISLA) research and theory has been implemented by Duolingo programmers. While current frameworks for the evaluation of MALL technology (e.g., Reinders & Pegrum, 2015) place a significant focus on the learning affordances available, less emphasis has been placed on the implementation of ISLA theory. As such, Chapelle’s (2001) evaluation framework, originally developed for computer-assisted language learning programs, is revisited due to its basis in ISLA theory. Six criteria thus serve as the basis of this evaluation: Language Learning Potential, Meaning Focus, Authenticity, Learner Fit, Positive Impact, and Practicality. While certain benefits of Duolingo as a language learning tool are discussed, overall the evaluation indicates that the benefit of Duolingo is more likely as a learning support app than as the sole tool for autonomous learning
