Blended learning in English as a Second Language (ESL) has become a growing trend in sustaining education at higher learning institutions. The impact of the Industrial Revolution 4.0 on education has made the integration of technology vital in the teaching and learning dyad. The COVID-19 pandemic has placed even more emphasis on the incorporation of technology in ESL pedagogy. Nevertheless, the reviews on blended learning in ESL are inadequate despite its great significance in sustaining education. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were adopted for reviewing current studies, and two core journal databases, namely Scopus and Web of Science, with two supporting databases (Science Direct and Mendeley) were utilized. A total of 32 articles were identified through a systematic search of “blended learning” OR “blended education” OR “blended courses” OR “integrated learning” AND “strategies” OR “techniques” OR “applications” OR “methods” AND “ESL” OR “English as a Second Language.” Four main themes emerged from this review, namely collaborative-based learning, learning management systems, social media applications, and technology-based learning. Finally, several recommendations were presented at the end of this research that should be the focus of future studies.