An increasing number of international graduate students who learn English as an Additional Language (EAL) pursue advanced academic degrees in the United States. Previous studies have indicated that international graduate students often face several challenges as EAL learners while socializing in English academic communities and negotiating multiple identities (Flowerdew & Wang, 2015). This study focuses on exploring the lived experiences of Southeast Asian international graduate students in a Midwestern university, grounded in the poststructuralist conceptualization of identity, Community of Practice (Lave & Wenger, 1991), and Language Investment (Darvin & Norton, 2015) by examining how Southeast Asian international graduate students construct their identities while participating in academic communities and their investments in language learning. The participants' reflective journals, documents, and interviews were collected to provide an increased understanding of the students' lived experiences and perspectives about their identity construction and participation in academic communities. The following research questions were investigated in this study: (1) How do international graduate students construct their identities in academic communities? (2) What challenges do international graduate students confront in participating in academic communities? (3) What opportunities do international graduate students have in participating in academic communities? The findings indicated that the participants constructed their identities based on their professional, learning, and cultural experiences. Concurrently, they confronted several challenges that include academic and social challenges as learners and international graduate teaching or research assistants. To be a legitimate and competent member of the academic community, the participants incorporated various strategies such as enrolling in additional English courses and receiving support from the academic community members and instructors to participate in academic communities. It was also found that their perspectives evolved as identities are multifaceted, complex, situational, and dynamic. Due to power relations in academic communities, participants struggled in gaining fuller membership and to be deemed as legitimate and competent academic members. The findings of the study contribute to the literature on language, culture, and identity through the lens of communities of practice. In addition, the findings inform educators in higher education institutions about the challenges that international graduate students face and ways to support them. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]