Tutoring is often touted as a way to overcome shortcomings of classroom instruction, either as a way to remedy unfinished learning or to provide additional instruction for students who are more advanced. There is evidence across different subject areas that tutoring can be effective in promoting student learning. Because the basic decisions about tutoring are made by tutors rather than those being tutored, this dissertation focuses on understanding the important thinking and the work of tutors. Through Self Determination Theory, Attribution Theory, and Goal Orientation, this dissertation uses a quantitatively driven mixed methods study with an explanatory sequential design with the point of interface during the interpretation phase of the study to examine the following questions: (1) What are the goals and motivations of K-12 tutors? How do goals and motivations vary by status (paid versus volunteer tutors), experience (how long someone has tutored), and tutoring context (in-person versus virtual tutoring)? (2) How do K-12 tutors understand the obstacles and successes of tutoring? Does this understanding vary by status (paid versus volunteer tutors), experience (how long someone has tutored), and tutoring context? (3) How do tutors describe specific instances of their goals, motivations, success, and suggestions for overcoming challenges they encounter in their tutoring? Does this understanding vary by status (paid versus volunteer tutors), experience (how long someone has tutored), and tutoring context? I reviewed contemporary literature to put the current situation in context, collected quantitative survey data from tutors (N = 211) to understand their conceptualizations of tutoring, and conducted semi-structured interviews with tutors (N = 13) to collect qualitative data to shed light on current practices and perceived obstacles to effective implementation. Using a mixed methods approach provides a broad understanding of how and why different tutors conceptualize their practice and in-depth knowledge about tutoring experiences, including suggestions for improvement. Understanding these perceptions is especially important due to the recent increase in attention to tutoring and expansion of tutoring programs as a consequence of the COVID-19 pandemic, which has created a tremendous disruption for education, revealing and exacerbating educational inequities that harm low-income K-12 students. This work will help identify future directions for tutoring, offer insight into how to implement effective tutoring programs on a wider scale, and offer considerations for tutor recruitment, training, and retention efforts. [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.]