In reform-based science curricula, students' discursive participation is highly encouraged as a means of science learning as well as a goal of science education. However, Asian immigrant students are perceived to be quiet and passive in classroom discursive situations, and this reticence implies that they may face challenges in discourse-rich science classroom learning environments. Given this potentially conflicting situation, the present study aims to understand how and why Asian immigrant students participate in science classroom discourse. Findings from interviews with seven Korean immigrant adolescents illustrate that they are indeed hesitant to speak up in classrooms. Drawing upon cultural historical perspectives on identity and agency, this study shows how immigrant experiences shaped the participants' othered identity and influenced their science classroom participation, as well as how they negotiated their identities and situations to participate in science classroom and peer communities. I will discuss implications of this study for science education research and science teacher education to support classroom participation of immigrant students.