The problem of practice addressed in this study is that online writing tutors in higher education are challenged to support multilingual adult online learners in the development of standard academic writing, including learners of different English dialects. The purpose of the qualitative basic study was to explore the challenges writing tutors face while supporting multilingual adult online learners in the development of standard academic writing. Social constructivism theory was used to bridge the gap between old concepts and new concepts of writing pedagogy used by participants to mitigate linguistic diversity challenges. Seven one-on-one semistructured interviews were conducted with writing center tutors at colleges and universities within the United States. Data were analyzed by coding, categorizing, and finally identifying four themes. The findings highlight the need for a more nuanced and inclusive approach to writing instruction that acknowledges the diversity of language backgrounds among learners. The key take-home message is that online writing center tutors need to be equipped with the knowledge, skills, and strategies to work effectively with multilingual adult learners. The potential impact for positive social change at different levels, including individual, family, organizational, and societal/policy, can be significant when it comes to promoting linguistic diversity in writing instruction for multilingual adult learners. At the individual level, promoting linguistic diversity can enhance the self-esteem and confidence of multilingual learners, who may feel marginalized in academic spaces due to their language backgrounds. By acknowledging and valuing their linguistic diversity, these learners can develop a positive self-concept and a sense of belonging, leading to better academic outcomes and social integration. [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.]