Within the past few decades, notable contributions have been made in heritage language education research that continued to gain ground in language pedagogy and teaching practices (e.g., Davila, 2017; Valdes, 2000; Fishman, 2001; Kelleher, 2010; Polinsky & Kagan 2007). This dissertation is guided by translanguaging and social identity, two theories that were previously investigated in connection with Heritage Language Learners (HLLs) in general, and Arabic HLLs in particular. This study investigates the effects of both translanguaging practices and social identity on the experience of Arabic HLLs in the classroom. Following a mixed-method design, quantitative data are retrieved from two 9-point Likert-scales questionnaires that target Arabic HLLs' perceptions of translanguaging and social identity in class. Qualitative data are triangulated from semi-structured interviews, classroom ethnographic observations, and class notes. Data from 72 Arabic HLLs who took the questionnaires and 17 learners who participated in the interviews are analyzed. Quantitatively, results of a hierarchical cluster analysis categorize HLLs into three main clusters based on their questionnaire responses. Qualitatively, a thematic analysis method is adopted in analyzing the interviews, classroom observation, and class notes. Results show general positive attitudes towards translanguaging practices in the classroom. Also, Arabic HLLs tend to align themselves with their heritage communities in terms of social identity. However, there appears to be mixed views on translanguaging practices in writing due to classroom effect and participants' personal language ideologies. Finally, results indicate that Arabic HLLs use translanguaging practices to mobilize their social identity in class. Pedagogical implications and future directions are discussed. [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.]