Scholars in the field of language education (LE), linguistics, and applied linguistics have been long advocating for more critical LE through bilingualism (Cummins [2000]. Language, power and pedagogy: Bilingual children in the crossfire. Multilingual Matters.; Nieto [2017]. Language, culture, and teaching: Critical perspectives (3rd ed.). Routledge.), multilingualism (Blackledge and Creese [2010]. Multilingualism: A critical perspective. Continuum.; Conteh and Meier [2014]. The multilingual turn in languages education: Opportunities and challenges. Multilingual Matters.; May [2014]. The multilingual turn: Implications for SLA, TESOL and bilingual education. Routledge; Meier [2017]. "The multilingual turn as a critical movement in education: assumptions, challenges and a need for reflection." Applied Linguistics Review 8 (1): 131-161.), translanguaging (Garc & iacute;a and Leiva [2014]. "Theorizing and enacting translanguaging for social justice." In Heteroglossia as Practice and Pedagogy, edited by A. Blackledge, and A. Creese, 199-216. Springer.; Li [2024]. "Transformative pedagogy for inclusion and social justice through translanguaging, co-learning, and transpositioning." Language Teaching 57 (2): 203-214.), and plurilingualism (Corcoran [2019]. "Addressing the "bias gap": A research-driven argument for critical support of plurilingual scientists' research writing." Written Communication 36 (4): 538-577.; Galante and dela Cruz [2024b]. "The fall of bilingualism: Teacher candidates' voices on the implementation of critical plurilingualism in English language teaching." International Multilingual Research Journal 18 (3): 254-273.) to realise socially just (language) education in the fight against systemic social inequality (Phillipson [1992]. Linguistic imperialism. Oxford University Press.; Piller [2016]. Linguistic diversity and social justice: An introduction to applied sociolinguistics. Oxford University Press.). This paper presents results of a meta-synthesis of 214 research studies with plurilingualism as a conceptual framework through Fraser's ([2005]. "Reframing justice in a globalising world." New Left Review 36:69-88.) critical social justice lens to answer the following questions: 1. How do research studies that use plurilingualism as a conceptual framework address issues of social (in)justice in LE? 2. What are the barriers to and facilitators of social justice in LE in empirical research on plurilingualism? Thematic analysis revealed that 201 out of 214 studies discuss issues of social (in)justice: diversity, including linguistic and cultural diversity, inclusion, equity, exclusion, social justice, inequity, and injustice. Analysis through Fraser's ([2005]. "Reframing justice in a globalizing world." New Left Review 36:69-88.) critical lens revealed multiple barriers to and facilitators of social justice through examples of mis-/recognition, mal-/re-/distribution, mis-/representation. The paper concludes with implications for research, policy, and practice.