The online student response system (SRS) is a technological tool that can be effectively implemented in English language classroom contexts and be used to promote students' active learning. In this qualitative study, "Socrative", a Web 2.0 software, was integrated with active learning activities and used as an SRS to explore English second language learners' (ESL) perceptions of the use of this tool. The results showed that both techniques (SRS and active learning activities) contributed to increasing the students' level of engagement, promoted their critical thinking, and stimulated their collaboration. This current research describes the benefits of SRS in supporting ESL students' active learning.