Multilingual college students often struggle with writing and revising for academic purposes. This dissertation explored the effectiveness of a Concept-Based Language Instruction (C-BLI) approach to teaching revision processes to college-level multilingual writers. Although a significant body of research exists on effective feedback on multilingual students' writing, little is known about effective ways to support their development of revision skills, an essential part of the writing process. In this study, I designed and implemented C-BLI-informed tutoring sessions using a visual, conceptual tool called a Schema of an Orienting Basis of Action (SCOBA) (Gal'perin, 1989) to promote students' development of revision skills and internalization of the concept of revision. Seven multilingual college students participated in the study. Data sources included audio recordings of tutoring sessions, interviews with the students, student essay drafts, and student-annotated SCOBAs. These data sources were analyzed qualitatively to understand students' conceptual development and revision of writing. Overall, the quality of students' revisions, conceptual understanding of revision, and revision practices improved. Students articulated their revision processes with greater specificity as the tutoring progressed and demonstrated strategic and creative uses of the mediational means (e.g., the SCOBA, the interactions with the writing tutor) to serve their unique trajectories of conceptual development. Findings also demonstrated the dynamic unity between cognitive and emotional processes; students' emotional reactions to revision shaped their cognitive development and vice versa. This study contributes to research on teaching revision, suggesting that the C-BLI approach can effectively foster deeper conceptual understandings and practical applications of revision processes for college multilingual writers. [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.]