This dissertation centers on competencies for K-12 online and blended teaching. Article 1, published in Distance Education, is the literature review, which compares K-12 online and blended teaching competencies. We found that online and blended teaching share personalization as the most salient competency, but that blended teaching competencies emphasize pedagogical skill sets and online teaching competencies emphasize managing the online course. Article 2, published in the Journal of Online Learning Research, is an analysis of selected literature from Article 1, which analyzes the modality in which competencies occur (online or digital context, face-to-face context, generic, or blended). Over half of the competencies analyzed were deemed generic, or not specific enough to denote which modality in which they occur, and 30% of competencies were for an online or digital context, and a very few competencies were specifically for face-to-face modality, and blended competencies made up Article 3 is a description of the validation of a Blended Teaching Assessment of five competency areas associated with blended teaching: (a) technology skills, dispositions, and digital citizenship, (b) technology-mediated interactions, (c) blending online and in-person learning, (d) personalization, and (e) real-time data practices. While the confirmatory factor analysis showed minimal evidence of validity, we believe this is an important first step to building an objective assessment of blended teaching skills, and the assessment should be refined and further analyzed if it is to be used for summative purposes. [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.]