This article reports on a systematic review of research studies published from 2010 to 2021 on the use of apps for learning in the secondary English as a Second Language (ESL) classroom. We extracted relevant information such as the studies' country/region, research design, sample size, students' age, apps' names to conduct a thematic analysis to associate the types of apps and their learning outcomes. The findings suggest that quiz apps support vocabulary acquisition, puzzle apps support vocabulary and grammar learning, platform apps support reading and writing development, augmented reality apps support increased engagement, and virtual reality apps support development of listening and speaking skills. The factors involved in the effective use of apps for learning in the English classroom include the use of quality apps to support the teacher's pedagogy, the profile and readiness of students to engage in digital learning, and the recognition that a classroom ecology is needed for effective integration of digital resources for teaching and learning.