Tutoring promotes student achievement, academic independence, and the reduction of anxiety. While ample studies support tutoring for enhancing student success, few address how to evaluate tutoring. This quandary led to research in building and testing a meta-model that identified the hallmarks of one-on-one high-quality online tutoring. Theoretical and data-driven models were constructed using a mixed method-grounded theory (MM-GT) design, and items were developed. Three latent variables emerged following exploratory-confirmatory factor analyses: tutor efficacy, student-centered, and instructional approach. The hallmarks of high-quality online tutoring were identified as: (1) Tutor efficacy of platform; (2) Use of multiple modalities; (3) Engagement evidenced as multiple back-and-forth utterances; (4) Appropriately paced interactions; (5) Use of open-ended inquiry; (6) Accessing and building on prior knowledge; (7) Support of student efforts and (8) Ensuring understanding through clarifying and/or checking-in with the tutee. Limitations of this study, implications for tutor management through quality checks, and further research studies are discussed.