Information communication technology (ICT) is increasingly used to enhance teaching and learning, but many teachers lack mastery-level experiences using these computing technologies in the classroom. To further their knowledge, some teachers have turned to online professional learning networks (PLNs) for development, but further research is needed to explore how and why these networks change teachers' practice. Framed by Albert Bandura's theory of self-efficacy, the purpose of this study was to explore the influence of online PLNs on teachers' perceptions of their technological self-efficacy for implementing ICT in the classroom. The research question of this basic qualitative study with interviews addressed how online PLNs influence teacher perceptions of their technological self-efficacy for implementing ICT instructional practices into the classroom. Purposive sampling was used to recruit eight teachers who had contact with an online PLN for over a year. The questions in the interview protocol were based on Bandura's four sources of influence for self-efficacy. Interviews were conducted using video conferencing software, and data were analyzed using two rounds of in vivo coding and NVivo software to confirm the results. Results indicate that online PLNs influence teachers' technological self-efficacy by providing resources, relationships, and opportunities to problem-solve. It is recommended to conduct a similar study with a larger sample across more geographical areas in varying school districts. Positive social change includes possible increase in administrator support of PLNs for teachers. Teachers' participation in these networks may allow them to implement ICT more consistently. It may also reduce professional development costs for districts. [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.]