Vocabulary is an essential component in language learning. In addition to its relationship with other language skills, such as pronunciation (form), reading (meaning), and grammar (use), vocabulary is required for language proficiency. In parallel, language learners must be equipped with specific amounts of vocabulary to comprehend texts of diverse genres (e.g., novels, newspapers, and movies). However, learning vocabulary is incremental, and this skill challenges many language learners in their language-learning journeys for several reasons. Nevertheless, emerging mobile technologies might mitigate the negative impacts on language learning (e.g., lack of motivation and engaging learning environment). In this regard, the present study evaluates a mobile app called WordUp using Kohnke and Moorhouse's (2022) framework.