This mixed-methods case study centered on an online professional development (PD) event targeting university-level teacher educators and higher education discipline-specific instructors. The topic of the online PD was disciplinary literacy and the promoted use of metacognitive modeling via think-aloud as an instructional strategy for secondary students in various discipline areas. The study aimed to understand how the use of the same instructional strategy by the PD facilitators affected participants in terms of changes to (a) their knowledge about and attitudes towards reading instruction in the disciplines (e.g., mathematics, social studies, science, the arts); (b) their beliefs regarding learner-centered/non learner-centered classrooms; (c) their general teaching philosophies; and (d) their self-efficacy to use and teach the strategy to others. Specifically, it looked for any relationships between these changes, their intention to apply the same instructional strategy in their own classes and/or teach their pre- and in-service teachers the strategy, and participant perceptions on the importance of the strategy to their learning. The online PD was accessible over a period of four weeks in the winter/spring of 2012. Ten participants from various institutions took part in this study by completing surveys, submitting metacognitive modeling samples pre- and post- PD, and participating in interviews. All participants experienced change during this PD event through the acquisition of new knowledge, while many showed resultant changes to their attitudes and beliefs. Changes in knowledge were most evident in the pre- and post- metacognitive modeling samples the participants provided, with increased scores indicating improvement in their ability to use the instructional strategy. Most evidence of other change is found throughout their interviews. Overall, the participants rated and ranked the metacognitive modeling example videos provided by the PD facilitators as nearly integral to their learning. The largest limitation of the study was the small number of participants. Discussion discerns the nature of teacher change, provides suggestions for future PD design/research, and asserts that the goal of PD, traditionally to result in changed teaching practices in the classroom, instead be to provide the knowledge and initial experience educators can use as a foundation to change in all areas. / text